Can The Rule of Cool Go Too Far? Daggerheart Playtest & More! | I'd Crit That: A Couples D&D Podcast 

Rule of Cool Story: I was running a Spelljammer campaign, and the party was on a rescue mission for a downed ship in the jungles of Chult. The party makes it to the scene of the crash, and the surviving crew is starving, and under attack by Pterafolk. At the height of combat, the captain of the ship is taken by one of the remaining enemies. The idea was to have the party either track them to the Pterafolks' roost or prioritize the crew, who was severely wounded and starving. My Paladin got the wild idea to load himself into a mangonnel and fore himself at the Pterafolk. I *probably* shouldn't have let that happen, but he managed to score a hit at long range with the mangonnel, at disadvantage, even, so I allowed ot to continue. He made an attack on the enemy, managed to kill it, and saved the captain, nearly killing himself and the captain in the process. They were both unconscious for several hours because he was the party's primary healer at that moment but were stabilized, and I got to improvise a standoff with some zombies at the shipwreck as a result, because the commotion from the airborne smite coupled woth the pair of humans crashing to the earth stirred up some slumbering zombies. Shit was wild.

My rule(s) of thumb for the rule of cool: Is it in the realm of possibility, and does it add to the scene, the character, or the story. If yes to any 2+ of those, auto yes. If 0, "no, but". If it's possible but doesn't add anything (rare), I ask questions to see if we can get it to add anything.

I just wanted to add one more theory to the AITAH conversation... the GM might not have had much if any experience with essentially firing a player. If that was the case, they might have leaned on having the rest of the group there as back up to be able to do it, consciously or unconsciously.