I also wanted to do this...but think about the mechanic in the context of the game. You're determination makes it so that you can come back from death. In order for them to take your soul, you have to stop doing that, and let the timeline move on without you.So...in order to give them your soul...you have to die and then quit and never come back. Because by coming back, you're just rewinding the time and undoing what they were probably doing with your soul while you weren't conscious of reality.