~Angel~

Ok so in Pink's fight, Pink's soul has to come to terms with the fact her body has become her own separate person with her own thoughts and wishes. BUT, Pink's body cannot function without the soul and the soul loses her autonomy to some extent without the body.

This DIRECTLY mirrors the relationship with us (the soul) and Kris (the body). Kris obviously can't go long periods of time without us controlling them and we lose alot of our autonomy without Kris.

Pink's soul is shocked when her body begins thinking and moving on its own because, until that point, she possessed a figurine, not a darkener. We, as the player, have that same shock after transitioning from Undertale to Deltarune.

In Undertale, Frisk was a mostly blank slate that we could project ourselves onto. No known friends or family pre-fall. They never fight back against us or project their own thoughts onto our actions. But Kris does. They disagree with us. They fight back. They have their own family, history, hobbies, and interests. They do things we disagree with and we do things they disagree with.