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.
Uh, no. Chemilo definitely, has something left at the end, but taticly screwed up and was in a bad position at the end. Yet he instead tryed to force himself through, screwing up Edris. Mo was actually looking to ty up, and Edris was catching him, and was about to overtake him when Chemilo rammed into him, causing him to lose his balance and fall.