I've recently visited Drill Sergeant Dornan, and agreed to attend guard duty for him. I was wondering if this guard duty ever ended, because I've been waiting at the vertibird garage for ages. So is there an official end to this guard duty, or do I have to just 'desert my post'?

You just have to leave. He makes rounds and after the first time you're missing you get a warning. I don't know what happens after that 'cause I never ran into him again.

Alright, thanks.

Yeah, the trick is to avoid getting caught and forced into guard duty.