As this guy is a protagonist, I'm going to have him try to escape and nearly succeed. Right now the plan is to have him swing himself towards the bars, and hook his legs through them, so that the pressure is off his arms while he picks the lock on the cuffs*. While checking to make sure that this would be plausible, I hit upon several helpful tips for escaping from handcuffs and several stories about Houdini escaping from a straightjacket in mid-air, but nothing about escaping from handcuffs while having to deal with them being chained to the ceiling. Does this still sound do able?
Search terms used include various combos of: "escaping from manacles" "escaping from handcuffs" "escaping in mid-air" "escaping from hanging in chains" and "how to".
*Cuffs are less modern-day police cuffs and more Victorian irons, with each cuff connected by a chain about four inches in length. Lock picking of all types is a life skill for this guy. More than anything else, I'm worried that it would be impossible to pick from the position he's in.