The driller shooter was carrying boxes into the blasting magazine. EE bumped EE's hard hat on the door frame, and when EE went to grab it, EE slipped on the magazine floor (raining and muddy). When EE's weight re-distributed to EE's right leg, EE felt it pop at the knee, which was a ruptured quadricep tendon and right thigh muscle. The knee was professionally immobilized.