He's a hacker, just hiding it. I used to play like him before I went legit.
From 2:00 onwards he was following a guy using chams, obviously, then brushed it off by taking another walk around the place so the guy could run towards tower.
Notice at 3:49, he doesn't check the other roofs around him cause he was looking at the one above him with chams, not moving until the other guy did.
I'll edit n post more when I finish watching it.
Edit: oh fuck, I found too much to post in the rest. LOL. I cbf explaining all of them to people that are amateurs at hiding hacks.