Scourge was cocky and arrogant, but he was never stupid. In a prison where he was essentially powerless, bottom of the food chain with a pissed off King Maxx and his goons, and nothing to offer for joining him...
Until he saw his new cell mate eyeing him up, memories of some movies he'd seen coming to the surface. It wasn't ideal, but he would at least have someone watching his back. Heck after the first few times, he learned something new about himself, and had some bad news for Fiona when she eventually busted him (And his new beau) out.