There's no elevator that she can see, just a smooth concrete wall and a hallway going off to the left. On the concrete wall where no elevator is are a pair of signs set into a holder attached to the wall. One of them is labeled "Executive Affairs" and the one below it is labeled "Central Executive", and both of them have arrows that point down the hallway. 

That sure is a distinct absence of an elevator.

She stands for a moment, staring at the place where the elevator isn't, and then sighs and follows the signage, moving slowly and peeking around corners before she turns them.

There are wood paneled walls, and glass windows into meeting rooms and offices, a red carpet as she walks, and the walls have paintings and clocks and benches and other high-end office accoutrements, the aesthetics still looking like something out of the 60's.

After she's gone down the wending hallway a short ways, the same crackling disturbance she heard on the way back from getting the gun is heard again, and the same shadowy outline of the dead man in the office is overlaid on top of what she sees. The voice fades in and out again, like something trying to communicate with her and having a lot of trouble getting through the static, though there's no sense of urgency or difficulty in the voice itself. 

".....the Hotline...." 

"..secure line of communication...." 

".....guidance....."

".....reach the Hotline.."

Can you hear that? Weird. Wish I knew what he was talking about.

She keeps moving. The place looks very peaceful but after... whatever that business was with the red light and the glowing zombies... she doesn't trust this charmingly antique office any farther than she can throw it.

A short distance further past a turn in a hallway, she comes to a more open area. In front of her, in said open area, is a large meeting room, and in the meeting room is a person in a slightly-outdated-looking business outfit, a button down shirt and slacks, floating in midair like they're hanging on a coathook, much like the security guards had been, before they dropped down to try and kill her. 

...she squints suspiciously at them. Unlike the security guards, they don't look equipped to do battle, but honestly that kind of makes her feel worse about the prospect of them suddenly trying to kill her.

As long as she doesn't move any closer, they don't make any sort of movement, simply hanging in midair without any sort of sound or gesture. 

All right. Fine.

She takes a few more steps, holding her new friend ready by her side.

The floating businessperson does not move or fall from its hanging perch. 

What does happen, however, is there are several strange sounds and red flashes in the open office area barely visible to her left, and then several more tan-uniformed security guards come towards her with their weapons drawn, their heads lolled over to one side as they jog. 

"Fuck!"

Cover, cover, where the fuck is cover—she dashes for the concrete column at the corner of the meeting room, leans out around it and starts shooting. The wood panel next to the column looks comfortingly solid to her eyes but her brain is uncomfortably aware that a bullet would go through it like tissue paper. At least they can't see her through it, though.

They cannot in fact see her through it but they are aware of where she is. Or at least, appear to be aware of where she is, it's unclear where their seeming intelligence is coming from. A bullet whizzes through the wood paneling past her right side and she can feel the hairs on her arm move and there's now a giant crack in the paneling. Another bullet makes the crack wider, knocking a chunk of the paneling out so she can now see through it to see one of orange-glowing security guards approaching her via the meeting room. 

"Shit," she mutters, trying to line herself up more tightly with the column so there are no bits sticking out for them to shoot at. But it's a pretty thin column and she has to be at least a little exposed if she wants to shoot back and why is there not better cover around here? Probably because whoever designed this office wasn't thinking about conducting firefights in it!

They're close enough now that it's worth trying for headshots. How many of those does it take to put one of these guys down? Let's find out.

It takes about two headshots, it turns out. Or a headshot and a body shot, if she misses her second (or first) headshot in a correct direction. Hitting an arm and then the head won't do it, though. 

The guard approaching from the meeting room is close enough so that she can easily get two shots off right in the head, and as an added bonus, the glowing blue dots are near enough that any wounds she takes from shooting the other security guards are quickly healed away. 

Once she manages to down them all, she has time for a single breath before there's a couple more red flashes and whooshing popping sounds, and two more security guards appear at the far side of the room, coalescing out of the strange multicolored smoke, before turning towards Jesse and marching towards her with their weapons drawn. 

"Fuck you!" she hisses at them, retreating behind the column again to shelter herself while she takes them out.

Being only a couple of them this time, Jesse manages to take them out without difficulty. 

This time no more security guards with glowing orange light under their skin make themselves known, and Jesse is free to wander around and explore the space. 

It's a rather large space, full of, well, 60s office equipment. There's a large red-carpeted area with dozens of desks in neat rows of three, each with its own typewriter and reading light and inbox and outbox, a couple with binders stacked precariously high, but most kept reasonably neat and tidy. There's a column with decoration and planters and benches on either side, and other benches placed against the walls of the room in various locations. There's an area somewhat out from the wall made of a dark stone that looks somewhat like the stone from the astral plane, though this one is slightly less shiny and has white speckles instead of gold veins; the outcropping is large and rectangular and labeled SHELTER in large white painted letters, which underneath written in the negative space in a yellow strip in slightly smaller letters is written "MAX OCCUPANCY 6 PERSONS", and further even smaller white-painted lettering beneath in small blocks. There's other desks in various positions throughout the room, most of them larger and clearly more important than group of smaller desks. There is a wall covered in filing cabinets, with tiny paper labels that Jesse is unlikely to be able to decode at the moment. 

Oh, and there are people, hanging in the sky, in business outfits, both male and female, and all of them and chanting something very quietly in unison, so that it sounds like whispers gently from behind a door. Whispers that feel like drilling in the back of Jesse's skull -- muted for her now, but still incessant and unending. Whispers that remind her of how she felt when she first heard it, the pain and the drilling and the horror. 

Wow, those whispers are really viscerally uncomfortable to listen to. She does her best to ignore them.

After a slow circuit of the room to make sure there aren't any more glowing people lying in wait, she tries opening the Shelter to see what's inside. Is it going to be more glowing people? She hopes it's not more glowing people. She could do with fewer glowing people.

The shelter might be a second to figure out how to open, but the button is labeled properly. It slides open with obvious mechanical sounds, and Jesse can see that it's a block of this stone set in more of the stone, being moved by a gear underneath the large block of stone. It sounds big and heavy to move, and likely is. 

Inside the shelter are some supplies, and a floating whispering businessperson. 

...she can investigate the supplies while keeping half an eye on the floating businessperson. Why are there floating businesspeople. Why is this a thing.

There's food (MREs), water, and clothing (including a set of six hazmat suits), along with some ammunition (but no guns), and a chemical bucket for going to the bathroom in.

Are there regular incursions of glowing people around here? She feels like... not. She feels like this is the sort of shelter you build when you have no idea what you're going to have to shelter against and you want to be prepared in general as opposed to prepared for the specific bad things you're expecting.

She gives the floating businessperson a wide berth on her way back out. (She still can't make out the words, and it's like an itch inside her skull, the not-quite-sense of them.)

Okay, what now?

Near the shelter there's a sign labeled "Central Executive" with an arrow pointing to a doorway out of the room. She could also look around "Executive Affairs" a while longer if she wants to. There's some posters on the walls, and there may be useful files around on people's desks for her to read. 

Sure, okay, what do these people's motivational posters look like. Is there going to be a kitten hanging from a branch.

There are no kittens hanging from branches. 

The first one is a white crosshair against a red background, with large letters exhorting the reader to "Avoid Modern Technology!" The bottom of the poster says "Synchronicity research department". 

The next one has a creature named "lumpy" which looks approximately like a greenish-brown lump of fecal matter against a red background, with a nametag and bowtie and arms and legs and heels, with the admonishment "Don't Let Mold Hitch A Ride!" and then beneath explaining to the reader than they should "perform daily body checks for foreign plant matter". 

A third one has a stapler that is standing up and winking, with arms and legs, with large text asking the reader "Is that a stapler or an altered item?" and then below telling the reader "Don't take office equipment outside of the building". There are even more posters, if she wants to look around for them. 

Still better than the kitten.

But she thinks she is done with the posters now.

After a brief glance around that doesn't turn up any more obviously bizarre things, she heads to Central Executive.