I'm back to the aliens for the limp. During the Teller character's sleep on the cot some itty bitty chicken-chit little aliens, eco-conscious aliens at that, transported / teleported in to his leg. As punishment for riding motorcycles (not eco-friendly), riding them too fast, discharging firearms regularly (discharge of hazardous gasses [not to mention lead], for smoking (hazardous gasses again) and too many other not eco-friendly things to mention the little bitty green-plaid alien bastards are screwing with him. They'll start in his leg, work up to his... uh... private parts, he'll be humiliated by the ED, then will drive his new Glide head on in to a semi at the end of the show just like the Ed Harris character at the end of the movie Knightriders (awesome movie by the way!).
At least that's what I choose to believe is going on (it's as believable as the actual show is.....).