Revealing mistake: During the opening credits, just before they discover the hotel, 10K fires a round from his rifle. This strikes a medallion hanging from Doc's neck and the bullet ricochets and kills a zombie. 10K ejects the spent cartridge from his bolt-action rifle. This cartridge spins in the air and lands on rocks; however, what lands is not a spent cartridge, but a live round, with bullet intact.
Question: When did Lt. Mark Hammond get the scar on his face?