After the first round of battle with the Quincy's, almost everyone was either dead or hurt badly. Including your captain, Kenpachi. Now, you and Kenpachi were close, you being the stand in Lieutenant if anything were to happen to Yachiru, and the fact he couldn't keep his hands off you.

He always had to be touching you in some way. Whether it be a hand on your waist or head, or on the usual occasion he'd pull you into his lap. You were the love of his life, everyone knows that. He was always like your guard dog, even though you could very much handle yourself.

So when you got to the squad 4 barracks, the med squad, with a cut in your side from a Quincy arrow, walking perfectly fine, but he flipped. He was hurt himself, having pretty minor cuts and gashes. He was already pissed the Quincy's got away, but seeing you hurt sent him over the edge in anger, protectiveness, possessiveness, and panic.