I don't understand what I'm apparently not seeing. Gionta turns around looking for the puck, he has to skate in front of Reimer, staying outside of the crease, when Gionta attempts to get the puck, he needs to shift his body so his back is to Reimer. Reimer trying to follow the puck, moves towards Gionta, which causes Giontas elbow to strike Reimer in the head. Both players were following the puck, and there was too little room in the area for all 4 players.