When an evil character is in the same vicinity as a good character, usually something devious is going on. Sometimes, though, the villain just doesn't want to fight. Maybe they just finished a hero/villain teamup. Maybe they're in a neutral zone, and they can't be overtly hostile. Or maybe the evil one is just Genre Savvy enough to realize that sometimes the best way to hit somebody is to trick them into crawling down to evil's level. See I Shall Taunt You when this scheme is employed deliberately as a part of a larger plan, usually a Batman Gambit.