What are some other reasons you think the girls might've killed themselves?

I'm trying to get a more detailed image of what the plot could be so I have better chances at finding the anime. OP's original reason on why they killed themselves was that after being trapped for days, the girls realized that they would inevitably starve to death. Something about this explanation seems off to me. Like why would they scream and yell after days of starving and losing hope? Not only would it be futile at that point, but they would've already lost the physical and mental stamina to do so. Another thing is that if they are in what I presume to be a public or school bathroom(there's running water, so I find it unlikely that they would be in an abandoned house or something), why wouldn't there be anyone else who needs to use it for all those days. There's probably many ways to justify OP's original claim, but I think OP may have forgotten some details and that there could other explanations that fit the plot better.

Personally, I speculate that its more likely that if the anime exists, the girls killed themselves in the first few hours of being in the bathroom. Instead of being trapped, they locked themselves in to escape an imminent threat(murderer, rapist, monster, etc.). After their philosophical conversations, they decided it was better to die than to suffer the fate of what's outside. Another possibility could be that the girls were trapped and their deep conversations involved the stress going in their lives. After finding that they all lived pretty horrible lives, they decide that their lives are not worth living.

These are just two possibilities I came up with. I'm sure that there are people that know how the plot of goru anime progresses more than I do? So I'd like to hear your thoughts.