Actually, it could be open for interpretation. I always thought it was Bobby stabbing himself that did it, and the show has always seemed to act like that's it. But yea, Zach did use that as a threat against Dean when he was trying to "convince" Dean to say yes to Michael. But his threats to Dean and Sam were ended, so I don't know that his threat to Bobby really went through...but not sure.

I guess we're supposed to assume that this is the new-and-improved post-Ruby Sam. It sure seems like Sam is assuming that.

Well, Sam always does like to think a LOT of himself, LOL! Boy is never short of arrogance. So, yea, doesn't surprise me that he thinks he can handle it. Idiot never learns. I just hope Show doesn't actually have him be able to control Lucifer in some way, even for a second, cause I'm gonna cry "FOUL" and "BS" as loud as I can if they do.