Okay so what do you guys think of the hypothesis that this is genuinely a group call?
And so in this moment, one of the callers is speaking to another third caller. For example, Rudy speaking to Carol, or Carol speaking to Asgore.
One thing that makes this feel possible is that in the final call of chapter 4 normal route, the voice says
>Kris...
>don't forget, Kris...
>...you promised.
The voice(s) at the other end of the call are willing to directly address Kris as "you". That means that if there's only one caller, then pic related becomes strange. If it's not a speech quirk of the caller to always refer to Kris in third person because they're the knight and sanity-damaged, then it seems to make more sense that there's multiple people at the other end or multiple lines connected in the kitchen scene.
This lets Carol possibly be the person who says they are coming to the house while still letting the knight go to the church. And the hospital is closed when the rain starts, so we can't prove Rudy was there.
AND there are multiple fonts used in the call. One is Red, and that's which one says "Susie... must not get... guitar..."
But the font when Kris calls in the closet is white who says "I'll be... right there..."
The fact it feels like the dialog is "broken up" in the kitchen call could be that we the soul are far from the phone, but it could also be multiple people at the other end having a conversation and not speaking directly into the phone at all times.