Just wondering, did you ever notice that *other* cyclist that went by in the background just as John gets knocked over? He’s riding from right to left across the screen, but he’s on the right side of the road, so he’s going against traffic and maybe would’ve had to go around the truck or come from the sidewalk to get that close to the curb. Seemed odd, to me. *idunnoprobablynothing*
I don’t consider anyone who was on the street after the fall above suspicion, though I do think it’s also possible they threw a couple of genuine random passersby into the mix. So I’m not sure what to think of the second cyclist. Just the fact that he was there makes me wonder about him, but he didn’t seem to get very close to what was going on as far as we could see. And he definitely didn’t stick around. One possibility is that he was an extra assigned to play a random guy on a bike for the sake of making it less clear that the BMX Bandit was specifically there to help Sherlock.
As for his strange path, we could (just barely) see in the overhead shot that he came in riding across the street on a diagonal. That’s obviously bad in terms of road safety. But maybe the excuse was that he wanted to get closer to the accident and see what happened, only to keep riding when it looked like there were already medical professionals dealing with the situation. Who knows.
And really, no matter what he was doing, he wasn’t a very careful cyclist. Whether he’d ridden on the right or left side of the road, he’d still have been going against traffic because he was riding the wrong way on a one-way street. (See the Google Street View image above.) But that could simply be a matter of his not wanting to ride all the way around a one-way loop to get where he was going. Or from an out-of-story perspective, the fact that they did want him in the shot, but didn’t want him to ride off in the same direction as the truck.