Boothill does manage to see the hatch and realizes that must be where he's got to aim. But Mei is getting too close for comfort to that cyborg goblin, yelling at her to not get too close, but it's too late and a well aimed punch at her shield causes her to lose it.

Boothill sprints between her and the goblin, using his body as a shield, pointing his gun at point blank. His body is durable but the arm can be torn off.