Hmm... I can't say I'd remember the early Buggy arcs that well and while it's true he would rather save his own skin than help his crew, I don't recall him especially sacrificing them. But then again, I don't remember those arcs that well, so maybe he did (did Luffy witness it, though?).

Mr. 3, however, didn't do much outside of Little Garden, so I don't really know how he even could have betrayed his own underlings.

Anyway, it was just my theory. I'm not saying Luffy really is behaving like that. But if he did, it'd make sense.