I'm assuming that's what happened. During PT one day, I didn't really see what happened, but for those who went to MCRD San Diego they'll know what I'm talking about, but the portion of the PT field out by the airport there is an actual stretch of track that you do two laps around and then after that go straight down a dirt path towards the main gate. on my second lap around he was on the ground towards on one of the turns of the track and our junior drill instructor was standing over him, and the Senior Drill Instructor was squatted down next to him talking to him. Neither of them were yelling at him which was obviously unusual as we were only like 3 weeks into Boot Camp and he was basically laying on the ground. He had dark read hair, and his face and neck were the same color as his hair. That was the last time I saw him. That same Junior Drill Instructor was my Drill Instructor for the Crucible. During the Crucible they essentially break you into squads with a Drill Instructor as the Squad Leader and start to treat you a little more like humans, and actually talk to you, and I remember him talking about that kid and telling us he had like a lung or heart problem of some kind and that he had actually collapsed from running too hard.