Perhaps they would have believed that they could have likely done it much better than the other two groups if they were put in the same position.
With that kind of thought process, they could dismiss the achievements of the others and just tell themselves that the other party was just lucky.
It would just be explained that it was a matter of a lucky encounter that resulted in those two groups being able to get there first to claim the chance to earn those bigger contributions for themselves.
They could just tell themselves that the other two groups had already been greedy enough to keep those opportunities to themselves and had taken the risk to do so, but got lucky that they never had any casualties from all of it.
It could be explained that those two groups were pushing their luck by trying to go for even greater contributions to the point that they had overestimated their capabilities, and that had ended up backfiring on them at that time.
