Joel heard the sound, saw the sledgehammer get knocked away, and decided not to bother trying to grab it up again - too heavy, and it would throw him off-balance, to boot. He was already in enough pain, and keeping away from the kid's clawing, punching hands was giving him enough trouble.

Jan's fist managed to connect - not with Joel's nose, but with the side of his head as he tried to keep his face away, and he grunted in pain again as black spots bloomed in front of his eyes. Jesus, another hit like that and he'd definitely have a concussion.

He smashes his fist down, hard, at whatever part of Jan he can reach, intending to do at least enough damage so that he can get away, get to safety.