You shouldn't be in Vault 34 unless you're level 20+. The amount of enemies in it may be too much for some players below that. I suggesting bringing in a flamer, or a riot shotgun.
You can take it at 10+, just be ready for lots of close combat with ghouls (shotguns, SMGs or an assault carbine). Bring some backup (I did it with Veronica and EDE) and a bunch of radaway and Rad-X, because the whole thing's irradiated. A radiation suit's not a bad idea, but is lousy as armor. If you wait until later levels the enemies will just scale up; you'll have to fight a Reaver, but you can shoot him from outside his office and he'll just stand there and take it.