Survivor seemingly self-inflicted dying state at exit gates. Is this a bug?

To preface, I'm fairly new to DBD and play mostly killer. I encountered strange behavior in the game and wanted to ask more experienced players if this was a bug or, in fact, some feature/perk I'm unaware of.

I just played my second/third game of The Shape, who I bought recently, and the game state was all generators completed, exit gates powered but unopened, two players dead, one player hooked, and one player injured. Very shortly after hooking the aforementioned hook player, the only remaining 'free' survivor, Dwight, just...entered the dying state? I don't know how this happened.

On my end, I was using my only two perk slots filled with the Trapper's Brutal Strength, and the uncommon perk Whispers, and the Dwight only had Dwight's teachable perks. Is there a perk in game that would somehow lead to this Dwight seemingly self downing? Sorry in advance for my lack of game knowledge, but I wasn't comfortable submitting a bug report unless I was sure this was a bug and not something else.