To move the MQ along in my new game (I'm itching to get into Broken Steel and actually play through it) I went directly from Megaton to Vault 112. When I got there, a total of four Brotherhood Outcasts were standing around the military vehicles that are there. Previously I had discovered the location, destroyed the Sentry Bot of d00m, then went on my way before I decided to just skip that far ahead.
Anyways.
When I get there, the Outcast are just milling around, telling me to get lost. I complete Tranquility Lane and when I come back out, the military vehicles are on fire, and all the Outcast are dead!
The wiki doesn't have this listed as a random encounter.
What happened??
"Imagination Power" answers are also acceptable in light of no real canon response hehe.