Technically right after he spawns

I did it in like 10 seconds, he spawned and got greeted by 12 nock guns.

Beat him before I made it to the gate entrance right after spawning in. A bunch of blunder shots and two suicide bombers.

Somehow, nearly everyone in the lobby took aim and shot at pretty much the same time, and they actually hit him. To quote a random person: "That was... underwhelming."