Once the cops show up and tell him to? Because the cops told him to, that's why.

Note well: I am not saying that the cops are always right. I am not saying that we should all be good little citizens and obey whatever the authority figures tell us to do. I am saying that, in the actual world we live in, disobeying police orders will often involve painful physical consequences, almost immediately. You can argue about whether that should be. Fine. I'm saying that it is that way, though, and you'd better plan on it being that way in your situation before you decide to ignore what the cops tell you to do.