I sat in on a Cirque presentation about KA with some of the performers. Cirque stars train diligently for extended lengths of time in how to fall properly. I believe one of them said they will train for weeks and months on something as simple as a 6-foot fall before moving up to the death-defying heights. That being said, without a fight/stunt choreographer, there are a myriad of things that can happen. Head and neck injuries, concussions, collarbones, shoulders, arms, wrists, ankles, legs, pride, and insurance contracts can all be broken if your group just wings it with a stunt like that. Film and television have worked their magic on us to keep everything believable and realistic, and they all involve highly trained individuals and willing insurance companies, and plenty of understudies.
Ok, I'm off my soapbox. Don't do anything dumb. Even if you saw Johnny Knoxville do it.