If the player cannonically Exists in Indie Cross, what will happen if Niko meets Frisk?

I recently rewatched episode 2 and had the realization that the player would technically exist, because Niko can still talk to them (he looks at the camera, signifying that the player is us, the viewer, and therefore is canon) and we can see that the SOUL, aka the player, also exists (the battle box that shows up has the SOUL in it, and Afton also holds it in his hand in nightmare form, proving it does exist) So if Frisk and Niko end up in the same dimension, what would happen?