This is a weird theory I came up with this morning. If, somehow, somebody could open up a perpendicularity into the Spiritual realm using some sort of 5th Ideal Bondsmith power on Roshar, then somebody else on Scadrial opens up another Spiritual Realm perpendicularity, somebody may theoretically be able to travel through one perpendicularity into the Spiritual Realm, then exit out the other perpendicularity, since all time and space is one in the Spiritual Realm. Tell me if this doesn't make sense. I'm still waking up.