Had this been Ritsuka from earlier in her time in Chaldea, she would have struggled to follow much of that explanation. As it is, there's still probably a thing or two she doesn't fully get, but for the most part she understands the gist of it.

And the salient point she's drawing out of all of that...

"Wait, you mean this isn't a singularity that needs to be repaired?"

Or maybe he's just mistaken? Some singularities could get pretty strange, after all.