Bella was expecting to be slightly late to math class. This is not math class, but it seems like the sort of thing she ought to be later to math class in order to investigate. In she stalks, ready for something to jump out at her, wondering if she ought to pull a stake out of her bag.
"It's also very thematic, but the rent part became more important when he stopped looting the bodies of people he ate, so."
"Hey, Bar, you apparently see multiple-worlds shenanigans all the time -"
Yes?
"Are things like me looking like his sister-in-law and him talking like my boyfriend common?"
Reasonably so, yes. I can't verify what's going on in those particular situations without seeing the missing parties, but there are plenty of cases of people having alternate universe variants.
"Innnnteresting."
"Would you be able to tell if Sherlock were here?"
Yes.
"Yeah. Um, my Watcher is way more easily ruffled than I am and I don't relish seeing him ruffled except when I do, are you gonna be reasonably non-ruffly if I write on my paper airplane 'hey come to the math room' instead of just 'please fetch me Sherlock'?"
"I can try. Failing all else I do have a second personality to fall back on."
It reads, Magic where there is usually a math room, check it out.
Bella waves him in. "Hi, Giles. This is a magic time-pausing bar called Milliways. I've been in here for a couple hours. That guy is named Mark and he is from the thirtieth century in an alternate universe, and the bar is sapient and conjures up beverages and copies of Vanity Fair out of nothing while channeling Miss Manners into neatly handwritten napkins."
"Also we sparred - me and Mark, not me and Bar - and in that as well as other ways he occasionally reminds me of Sherlock. The door will disappear if there is nobody from our world behind it and it closes. I am hoping I can send you on an errand to Sherlock's to wake him up, put him under something opaque, and bring him over to meet Mark. And since the door's closure pauses time I will require a faculty note excusing me from math and allowing me to loiter on the floor outside the door holding it slightly ajar but not enough that anyone will notice what's behind it."
"He's an interesting challenge! Most things I fight, if I set them up so they can do six things and the first five are instantly fatal, they'll do the sixth thing, and I can use that to maneuver. Sherlock often does a seventh thing. And Mark occasionally picks one of the first five in a way that manages to not be instantly fatal."
"Yes. Unenhanced human. I just have a lot of training and I took to it well."