I'm curious as to the MO of the robbers here. Notice that the bike driver has already started off down the road BEFORE the robbery went south - accelerating when he heard the shots. Assuming a successful robbery, how was the robber supposed to get away? Run after his partner on the bike? Makes me wonder if the bike driver was all in on the thing to begin with. Could be that when he saw what was going down he was "I'm outta here!"
I think he was going slowly to give his partner a chance to run and jump on the bike. When he heard the shot, he lit out. The thieve looked pretty young. Oh well, live and learn.