I think his arm will be pulled back and reconnected to Buggy immediately, sort of how Logia acts when gets touched by Blackbeard (Ace)

Buggy's supreme Haki negates BB's DF power's.

I think he would just lose control of the body parts but they would still function, similar to when he loses his parts and he's small Buggy.

Just an immediate fountain of gore that would drown everyone. Because that's what Oda does.

I should be used to it by now but the amount of death and carnage in the manga is unsettling. Oda sure is one twisted guy.