Bella slips into the school by a side door; she just saw a thing and she thinks she's seen it in a book before and thinks it's supposed to be mostly harmless but before she wakes Giles up over probably nothing or kills a likely neutral demon she wants to check.
And she pushes into the library.
"Mmhm, just don't, like, yank your shot wild if I roll under the line of fire with an inch of clearance or something."
"I'll have to recharge it every so often but I already checked and local electrical outlets present no challenge to my universal power adapters. It would stretch credibility to imagine that I might run out of charge in one battle, unless we spend twelve solid hours disintegrating statues."
Here is a giant hole in the ground. It's dark down there.
It's probably reasonable to attempt stealth at least until the point where he can tell how many statues he'll need to disintegrate.
Gosh that's a lot of lumbering statue jobbies. They're dancing.
Miles picks a nice vantage, and then he starts shooting. The underground chamber quickly fills with the horrible screams of dying statues.
"Can you get me a path to him?" Bella murmurs.
He picks off a line of statues. They seem reluctant to touch their disintegrating brethren, which helps.
Bella moves faster. She charges, dodging and weaving. Statues suffice as cover when the dude in the middle takes exception to her approach.
There is a blurring scuffle and then Bella has his implement of mysterious magicalness and he has a snapped neck.
The remaining statues disintegrate neatly and quietly, without the cracks or the smoke or the horrible screams.
"I do not see any obvious loot here, but I can wait around without depriving you of your ride if you want to loot hunt."
There is a little loot but none of it readily exchangeable for US dollars, the principal currency in which plane tickets are sold.
Eh, you can always find somebody. Miles pockets some likely-looking objects. "Okay, let's go."
And he hangs out with Zeke and commits petty theft and decides to scrap the whole idea of buying a plane ticket because faking the necessary identity documentation would require too much human contact and stowing away in a luggage compartment is safer. This still requires him to acquaint himself with flight schedules and pick up supplies, though. And he'll need some means of transporting himself to an airport...
He loiters by the butcher's shop around sundown; when Bella doesn't happen by, he tries the school.