I've done it 3 times, the first and second time was tuff. My first one was with folks from LFG, we would make laps around the map and shoot Skolas when the opportunity presented itself. My second run was also with LFG people yet this time we sniped him to death. The leader had shit weapons so we had to carry him. My third time was with friends and was extremely easy. I was blessed by the RNG gods this week and got a Cipher on each character.