A hostage situation? That's most certainly not the wisest plan of action. Alibaba is one to hold grudges, very long, painful, violent, terrifying grudges. If you care about your life, return it at once and there may be hope. No guarantees though.
The simple idea is to duke it out in the Crucible with me and Lord Shaxx yell at each other of who can win at a glimmer bet, but why not give back the item that they need?