I died

Hate to tell you this, you got shot. It's a very common occurrence near military tents nowadays. People literally just tent camp and wait for people to line them up with a shot. There's a very small crack noise right when you died. Definitely got shot. Got to thank the Xbox Community for never coming together and just killing each other on sight. SMH

To further prove my point, if you put in a pair of headphones and you listen very carefully you'll hear fast walking right before you get shot, also if you look down and to the right of the zombie right on the ground by the sandbags you'll see the muzzle flash.

At 13 seconds, you can hear the killer draw their weapon.