It is unlikely and maybe he should run, but he's not sure his mother will leave or that he has the heart to leave her. It's a critical flaw, and one that has kept him away from the shinobi population.

Kisame's 'guess' is alarming. He's gone to such lengths to blend in and his features aren't indicative of any particular line. "You're very perceptive, Hoshigaki-san. Please tell me how you knew."