You were undercover in the enemy base. You find out that Ghost was being held captive, so you decided saving him was worth blowing your cover.

You walk into his cell, and Ghost slowly turns his head.

"If I wasn't chained to the wall right now.. I'd kill you..." Ghost says menacingly as he stares at you.

"If you stay in here.. You'll die.." You say as you tossed him the keys to the chains.