I can't tell you the circumstances of the 2 people shooting together but there is supposed to be 3 people in a groupe or at least two and an official scoare keeper.

Rule 5 says that an arrow must be stuck in the target or it must be witnessed by the other shooters in the group as a pass through. If it is a wittnessed pass through it can either be scored as agreed by the majority of the group witnessing or it can be shot over. If the arrow bounced off the target than it should have been scored as a miss or zero score. When in doubt about the proper ruling of a arrow hit or miss or whatever then an official should be called to make a ruling based on the information at that time.