I am 100% convinced our lack of options in this scene is because we briefly broke off the path laid out by the prophecy.
The prophecy dictates what we can say whilst on the path which is partly why the prophecy supposedly comes true no matter what we say or do.
That is until we find a loophole and force Noelle to be our puppet, as to what end however, we dont know yet.
Our lack of options here is because the prophecy, like a computer program, doesn't know what to give us as options.
Susie was never supposed to ask us "what we were talking about" effectively knocking us off the path, but then she doubled back and joked about it, landing us back onto the path.
Kris is called the "Dark Bead" in chapter 4 weird route and it states "broken off but still locked" which is what im using to support my theory that we created an opening to subvert the prophecy but we have yet to make our move.
I have a feeling we're going to have more scenes like this going forward since we're subverting the prophecy and it doesn't know what options to give us.
Assuming I am correct, that means the soul is directly connected to the prophecy which may or may not be a program of sorts similar to how undertale was just a game program that Asriel and Kris made as kids on their computer.

This is the most mysterious moment of ch4
What does it even mean?