User blog comment:Blackendedsoul/Unique Gomu Gomu/@comment-4754162-20120301052813/@comment-3425840-20120301060329

I Buggy's body too is needed to be "activated" to split up or else his body would have fallen apart into piece. And I seriously doubt that someone could detach his head from underwater (maybe Law can, but that is Law's power not Buggy's).

This gives me another idea, what if Buggy's body is by default split up, but he forces it to stay in one piece, so that when he is too shocked or attacked (like slashed) it auto-reacts backwards and he splits up? Just a hypothesis. Self refute: If that was the case then he would have split into pieces when he fall in the sea (the time when Shanks rescued him).