It could fit around her arm and has a trigger. The business end has glass instead of a hole—more like a flashlight than a gun—as well as three metal "fingers."

She picks it up, points it at a nearby wall, and pulls the trigger.

It shoots a blue sphere of light at it—

—and then opens a portal there. Or, well, what it actually looks like is an oval hole on the wall surrounded by blue light, but the hole leads to where the portal light thing is, and a similar effect can be seen there.

...Weird. She pokes at it with the gun.

It is literally a portal that feels like literally a hole.

A gun that makes holes. Right.

Presumably she can... go through the portal?

Yep!

Great. So can she use that to get out of here?

Not really, but there's a broken catwalk thing leading from the place the orange portal leads to that seems to lead... somewhere.

Something to do, at least. She follows the catwalk.

Catwalk, stairs, corridor and she finds herself in a room that probably used to be an office... a while ago. There are chairs and old computers with tube screens and something that could be servers but could be something else, too.

Not like any tech she's familiar with. How old is this place...?

State of decay and technology suggests "very."

Farther up ahead she reaches a room with a broken window to another room.

She is still lacking in ways to get around other than following the open path.

There is an orange end of a portal across a not-extremely-but-still-somewhat deep pit from her. The announcer voice pipes up again: "Some emergency testing may require prolonged interaction with lethal military androids. Rest assured that all military androids have been taught to read and been provided with one copy of the Laws of Robotics. To Share."

Must be a different sort of lethal military android. She's never heard of the Laws of Robotics, anyway.

She shoots a portal onto a close wall.

It opens to the orange end, and from there she can see an exit door across another pit.

Okay, so- go through, re-place the blue by the door, go through again?

"Good. If you feel that a lethal military android has not respected your rights as detailed in the Laws of Robotics, please note it on your self-reporting form. A future Aperture Science Entitlement Associate will initiate the appropriate grievance-filing paperwork."

If she decides to disrespect someone's rights as detailed in the Laws of Robotics they're not going to be in any shape to fill out some damn paperwork.

The lift arrives to another set of stairs. "This next test is very dangerous. To help you remain tranquil in the face of almost certain death, smooth jazz will be deployed in three. Two. One." And smooth jazz starts playing.

...Music?

...for a few seconds. Then it fades out.

So that's what it was like. Not sure she sees what all the fuss was about.

The next chamber has a large red button on the floor again. There is a glass wall directly between the button and the exit door, and on the wall to the right of the button there is an orange portal again. A bit up ahead to the right there is a pit onto which a cube-dropping cylinder is pointing.