Board Thread:General Discussion/@comment-26006155-20190820122909/@comment-26006155-20200106040021

Because everything I see looking at the lore says that Dimensional/Time travel is very important to the story.

Alphys tells Undyne that she's sending the others to a place where Chara will never find them. And I have no reason to think Alphys falls short on this promise.

Gaster was scattered across time and space. This isn't something that happens to someone randomly, you need to be playing with some really fancy mad science for this to even be a possiblity. And Gaster's followers wondered if Alphys were share the same fate. So whatever Gaster fell into in the Core is still there, and still operational.

Having at least a few people surive the obliteration of the universe is a small comfort that not even Chara can truly destroy everyting. And it also resonates with the existing lore about a time/space portal existing in the Core somewhere.