He seems to be behind the bus, when it slows and veers right before it attacks him like a killer whale.
Just watched the video again; it looks like the cyclist is actually in front of the bus. Looks like the driver got pissed that the cyclist was slowing him down; eventually the cyclist tried to get over to the right, the driver says "You ain't gettin off that easy!" and knocks him out. I'm sure there's more to the story than that...but that's what it looks like to me
