The common-law doctrine of retreat to the wall has been modified and is applicable in this jurisdiction only to cases where the defendant voluntarily enters into a fight, or the parties engage in mutual combat, or the defendant, being the assailant, does not endeavor in good faith to decline any further struggle before firing the fatal shot, and possibly to other similar cases. Harris v. People, 32 Colo. 211, 75 P. 427 (1904); Enyart v. People, 67 Colo. 434, 180 P. 722 (1919).

In the OP's case his friend voluntarily entered into a dangerous situation. He entered into the fight on his own accord.