He couldn't really keep an eye on him from there either.

I dunno. Looking at it again, I don't think there was anything principally wrong with following Martin around the street corner just to see which direction he was going in to tell the cops--if indeed that's what he was doing. After all, to observe and report, one must follow to some extent.

Leaving behind the debate of whether or not he was in the right to tail him, if he had been more careful about it, this wouldn't have happened.