You might want to X-post to c/relationshipadvice as well. That being said, the only one responsible for kidnapping anyone is the kidnappers. And no one should expect their friends or lover to kill their kidnappers. It would likely get you killed in the attempt. On top of this, these are all hypotheticals.
Someone who is using hypotheticals that they made up in their head against you is more worried about themselves than you.
It is not my place, but this person sounds like someone I wouldn’t even want to be friends with, let alone date. Friends are there to build each other up, not tear them down and add anxiety.