Given the scenario as stated, and assuming that I really am on my own here, then I’m honestly probably going to die here. The authority militia don’t have the training that the security corps do and they’re usually much worse supplied, I’m gonna have to rely on my wits and the fact that I’m used to witnessing horrors to get me through this. 

I may not know a lot about heavy machinery, but all things hot must at some point be cooled, and the water that cools it is gonna either be under pressure or exist as steam. That stuff’s gotta be piped and stored, and even the authority aren’t quite dumb enough to not label pressurised steam pipes. My first shot is putting a hole in a steam pipe somewhere between me and that thing, so slow it down or block it’s advance, the next shot I’m gonna take the time I’ve bought to aim and go for the head. Or whatever passes for a head.

If I have pals with me, all the better, but with the treatment these soldiers get from the party you can’t guarantee that they’re up to scratch with a modern military - if they were, they’d try to overthrow the government more often - and even so I can’t guarantee they won’t break and run when it charges. Everything I do must be based on the assumption that I can rely only on myself.