It's the whole idea.
The guy get's his hand chopped off. He's fleeing the cops. He picks up the hand, and runs into the woods with it pursued by cops, choppers, and dogs. He walks into a veterinarians office at the end of a hard day's one-handed running, and is able to intimitate the vet into sewing his hand back on. This is delicate microsurgery. A fully staffed O R with three skilled surgeons would be working on this in Grey's Anatomy. This veterinarian however does the job - if you'll excuse the pun - single-handed, and not only isn't T bag weakened by the operation, he rubs his wrist a couple of times, and he appears to be stronger. He somehow ties the vet up who appears only too happy to comply with whatever this obvious psychopath has planned, then kills him.
Later in the day T Bag meets this big trucker dude, hits on his daughter, somehow beats the guy up one-handed, and heads off in the guy's car without any police pursuit. At which point I don't know how to respond, other than simply to say, "Huh?"