SPOILERSSSSSS

Subaru gets to see a what-if segment of what might have happened (the person showing him these doesn't know if they're parallel worlds or really just the world calculating what would have happened) after he dies in certain loops.
Like Emilia bawling over Subaru killing himself after finding out Rem was in a coma, screaming WHY WHY would you do this to me.
Or Ram and Beatrice shocked that Subaru jumped off a cliff and killed himself.
Pack getting killed by Reinhardt after killing Subaru.
The one time where Sloth possesses Subaru and dies a very gruesome death while keeping Sloth trapped is a good what-if.
Since it was basically Emilia's fault and she knew it and had a front row seat.
Subaru realizes there's a possibility that those universe didn't cease to exist and takes this all very hard.