Vanilla is a product of Lussumo:
Documentation and Support.
I was thinking the same thing. Luke always came off as an utter fuck knuckle, but Mark, at least in the last few episodes, has been kind of charming and likable. But then, the world's biggest bastards tend to start out that way...
...this is it-
I wonder who did the mad scientist laugh?
I must say, though, the leap from "those bastards shot me" to "we need to seriously fuck shit up right NOW" was a pretty light trigger. Straw that broke the camel's back, I suppose.