The response action for transferring the ring is an optional action, whereas threats being triggered and Promise Keeping are required actions.
I've been thinking about this and I'm not convinced. How is taking the ring optional and
Promise Keeping mandatory. Both use the same language saying essentially do it, not you may do it. Isn't it the same as healing at a sanctuary when
blade tip is in play. You get to heal before the wound. How is this different.
The rules say that you lose the game if your ringbearer is killed. So if Frodo is killed, it is game over. The only way the game can continue is if Sam takes the ring. Sam taking the ring should have priority over anything else because the game is over if he doesn't take it. Assigning threat wounds or
promise keeping exertions when the ring bearer is dead, is playing after the game is over.
So if Frodo is killed, I think there are two options. Either Sam takes the ring and the game continues, or Sam doesn't take the ring and the game is over.