is there any quest involved with vault 19 before i go in and kill everyone. I would hate to fail another quest like I did in vault 3 or ncrcf becaused I didn't know any better.

Go inside and talk to people and find out.

Good advice to any question asking whether quests will be locked off through indiscriminate killing. (Hint: um, probably, yeah.)

lol "didn't know any better"