The game lasted 545 seconds, his overall damage was 372868.

372868/545 = 684.34 damage per second.

In otherwords, this is an obvious glitch and his real damage per second isn't even close to 2000+. To prove he was here the whole game, there were only 8 people from his team in the warzone scoreboard screen. That means his team did not have anyone who left, so there's a 95% chance he was in that warzone from the start. Hence his real damage per second is 684.34. Nice try though.

P.S. It really annoys me that there are people like this who try to cheat the system, making it necessary to dissect games to find out the truth.