After Bullet had destroyed the up going stream and held Usopp in his hands, the latter being unconscious and beaten up, with Luffy getting very mad by it, the fight began. You stayed with Luffy to fight as Zoro left by his command. Fast forward when the sky turned red and Bullet got into that robot form, Kidd lunged at him with others of the worst generation, Killer pushing him out of the way to take the hit but you were faster, pushing Killer out of the way despite not being in the same team.