After battle, the Fire Elemental Summon would explode doing fire damage around it. Since it follows the summoner, it does damage to its allies. One of my main character had that fire summon and it exploded, dealing fire and burn damage to my 2 follower. Upon getting burn, their message of "friendly fire" pops up and after getting hurt from burn two more times, they leave my party.
It would be awesome for a summon to die quietly and safely if it runs out of time and dies. It only explodes/poison/etc if it is killed by any sort of damage.