"Why is this skeleton so powerful?" Suddenly Kira asked them this quotation.
Previously, when all of them attack that skeleton, they are unable to kill that monster, and sometime later, the skeleton once again is able to recover his legs. You can say that previously Sam got distracted for a second and, because of this skeleton, got the time to recover. Wasting no time, Sam once again uses the concealment technique and approaches that skeleton. He already instructed all of his friends to disturb that skeleton while he will finish that skeleton. So right now Tony and the others were attacking that skeleton, or you can say that they were distracting while Sam already approach that skeleton.