They talked about just giving away the 10K BTX since they already made loads of money from manipulating the price by buying and selling their large quantity of bitcoin several times.
Good idea for a story, but this part doesn't seem plausible. Kidnappers tend to be greedy and even talking about giving money away doesn't make much sense.
Their arguing and greed, the and the interpersonal dynamics that emerge from the issue of who is going to hold and control that piece of paper with the Private Key is what the story is really about. Bitcoin is just the background. The real story is always and relationships and people.