Jericho had spent his life learning to judge position based on things other than sight. When he heard a shot, he spun. He took a guess as to which way the guy was facing, then fired through the wall at where he guessed the guy's torso was.
The massive gun roared, smoke pouring from the exhaust tube as the 20 mm round screamed through the wall, passing through flesh before putting a very large hole in the wall behind.
The American sniper bolted a new shell in, then ran out to see who he had obliterated.