Precommitment is relevant in a second way here. You have to (before being released) precommit to pay ransom after being released. Once you are released, your precommitment would force you to pay the ransom afterwards.

If you are incapable of rewiring your brain so that you will pay the ransom, there could instead be laws recognizing that contracts made under duress are valid. That would have the effect of precommitting.

This precommitment is disadvantageous in the sense that being released without it is better than being released with it, but it also increases your chance of surviving to be released rather than being shot for not having any ransom. Precommitments tend to work like that--precommitting to do an action that can only harm you in a particular situation can be overall advantageous because it alters the odds of being in that situation.