It looked to me like Edris was tying up regardless. He wasn't going to beat Farah. It did look to me like Chelimo pushed Edris a bit, which allowed Chelimo to get past him.
Chelimo had something left in the final 50 meters but no way to get around the 2-3 people in front of him, so he tried to squeeze between Edris and Farah. If Chelimo weren't boxed in he might have had a chance against Farah in the final meters.