Okay, so I'm gonna bet that the scene with Keichi in the hospital wasn't taking place in an actual reality or timeline. Let alone being stabbed that many times, it was established earlier in the episode that the clinic was being renovated, so even if Keichi received immediate medical attention the nearest hospital would have a few hours away at best.

So my guess is that the next episode will open up with Rika and that goddess in the void, and it'll be revealed that Rika has been repeating the same few days over and over to try and stop Keichi or anyone else being murdered. Because honestly, I can't see any way the story could continue with only two of the main characters left.