Koutarou listens closely to Togusa's words, to his worries. It's valid worries, certainly, and not impossible that something of those sorts might happen.

"As of yet, our experiences here still remain and matter. That is of course no guarantee that it will stay that way at the end, whatever the end may mean, but it is also an indication that it's possible that it will remain. Personally I would prefer to avoid the second, with the last being the best option out of all of them."

After all, he doesn't want to forget about the experiences that he has remembered. (And even though he doesn't remember the painful things at the moment, he would be of the same opinion if he did.)

"Yet, whatever it is that happens, would it feel right to you to not help?"