Creatures Caves

Only if they are actually suffocating, I would think, especially given the fact that they died... These can't really die of fright alone. I know that fever and being too hot can screw up respiration if it gets really bad though, so it's not implausible that they were having a very hard time breathing and began freaking out about that before they succumbed to the lack of oxygen (realistic reaction, but sad

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These also could potentially freak out if having organ problems that cause lack of oxygen too... I think if one's heart or lung organ died or stopped for whatever reason, or had some congenital defect that prevented them from getting sufficient oxygen, they would likely start to freak out for as long as they had left, since they will most likely start feeling like they are suffocating. It's a sad but realistic consequence of this response that an unnatural death is often more unpleasant for the poor things. For example, it's heartbreaking to see the panic in a baby born with a mutation that stops it from being able to breathe and to know this is why they were so afraid for their few minutes of life. It makes it easier to determine what happened to them, but without the response they would have not suffered, and instead just quietly passed on without a clue there was anything wrong.

Well, it's also possible these also had fear toxin or some kind of mutation that made them suffocate or made fear or fear toxin in their bodies that manifested when fever toxin showed up, but I tend to think the first explanation is a bit more likely, since fear or fear toxin by themselves are not fatal. The drowning response itself pretty much just measures oxygen in their blood and reacts to that with fear if it is staying low for too long, but it definitely shouldn't be fatal on its own, what would kill them is the lack of oxygen for their regular metabolic processes (if oxygen becomes low enough to trigger the drowning response, they are already in bad enough shape that their energy will start quickly depleting shortly after, and death will follow if the situation is not rectified...) It's also rather unlikely for a mutation to make the drowning response fatal on its own the way it's designed... in fact it prolongs survival a little bit by allowing lactic acid to store some energy for them while they are in a low-oxygen state. None of the reactions involved should be easy to mutate into anything that takes anything vital or makes anything particularly toxic, thanks to the chemical numbers I chose (and the lactate-pyruvate cycle itself cannot mutate at all). About the worst mutations related to the drowning response that I could think of would cause either just fear by itself, or muscle death (which normal lactate, muscle toxin, and most mutations already makes happen in normal norns).