So, I killed Fantastic from the NCR power plant after the quest turn in. NCR didn't seem to mind, and it didn't result in a karma or faction hit. It was an easy quest, but after all that running up and down the tower, I couldn't let someone take credit for my work, right?

Has anyone else killed a quest giver?

Killed Caesar. :flamethrower:

The quest was completed immediately without me needing to do anything after I killed him....