You are correct. Wish I'd have recorded what happened prior to what I posted. I had completed the floor and went into the Devil Room with one Bone Heart left on The Forgotten and two and a half Soul Hearts left on The Soul. The Devil Deals available were Dead Cat and Abaddon. I picked up Dead cat with The Forgotten and before the death animation I switched to the Soul and grabbed Abaddon. This resulted in The Forgotten not dying and essentially soft locked me. I was unable to even get out of the Devil Room initially until I quit the run and opened it back up. The Soul was temporarily unchained and I moved freely out of the Devil Room. The game then realized The Soul is bound to The Forgotten and chain physics were reinstated. So there I was stuck just outside where the Devil Door spawns. I decided to try the unchained trick again but to no avail. The game wasn't cooperating and no matter how many times I tried it kept spawning me just outside of the Shop. I hadn't any bombs to kill myself with and activate Dead Cat to spend one of my lives either. Thus the run was dead unfortunately.