It's impossible to judge because we have no idea what preceded that event. He wouldn't have done it for nothing. Maybe the other guy kicked him off first or had mugged someone of their phone.
Maybe the guy that knocked off the other guy was a secret undercover agent, and if you think I'm joking watch this series of videos. they're absolutely enthralling - better than anything that's been on the TV. Don't worry, it's nothing to do with Brexit, but more about the Panama papers. The nitty gritty starts at about 15:19. Don't think it's just another conspiracy theory. The evidence is very compelling. My theory is that Thomas Mair was paid off after his arrest and given a new life and identity somewhere, which is why there's never been a positive identification of him since his arrest. That's why the trial seemed to be a sham and why he probably wasn't even there. The letter was forwarded to him from the jail to make a reply. He's probably in Bermuda now living the life of Reilly. Good luck to him. He deserves it after his narrow escape from death.