Nah. I don't think it's about being heroic. Or 'anheroic', for that matter.
We should not have split up in the first place. It's, like, the first law of the horror genre. It opens us up to potential liability of splitting even further, when those who are concerned for the missing people try to find them while the others could not care less and want to do their own thing.
If you remember the first night, that's how everyone died. First, the hospital have separated Amanozaki and us from the group and killed her. Then the group split to find us, which lead to Uehara getting killed. Then they locked us up in a room and we nearly died there as well. What happened to the rest of them is unknown, but there is an implication that they didn't stay united. Mori had some bullets missing from his gun, even though Taketatsu did not have gun wounds, so I can only assume Mori wasn't firing at him. And we didn't find Sakimura, Sawada and Mitsuki until the very end.
Divide and conquer is the motto of this place. So far when there were more than one person, we managed to avoid the worst. Mori bailed us out from Amanozaki's corpse, we saved Mistuki, and I want to hope that we have aided Shiba as well.
If there were more people like Mori around when Taketatsu started cutting people, perhaps he would not have succeeded in killing them, either. There is a question of why Mori had a large knife wound, though.
There is also that case with Uehara's death, but the circumstances are highly suspicious and our memory too unreliable to judge what really happened there.
Generally, safety indeed seems to be in numbers. The more people are around, the more likely they are to notice that something is messing with one of them, and the more likely they are to help. Making a close-knit team out of separate groups of loosely related strangers would bring us a step closer to our freedom, I would think.