Both promised to meet each other in a field of flowers during the valentines event but somehow in the epilogue it seems like they are in a field of flowers but in a different world like she said she can't go back.

Also it seems like the flow of events from christmas to the epilogue until he was discharged was all connected, mentioning that they wanted to hospitalize him for long term (probably a month) from the end of the year and within that point she was already gone. I have no clue if she pulled some interdimensional shit like neouni for the latter end of the epilogue.

Also while I didn't get the onsen event yet since you can't slot that anywhere, I'm assuming it's within that different world but I have to grind before I can read that...