I believe Boba's ability reads:
roll one die.
No matter the result, every enemy on the board insta dies, because he is boba fett.
Weird, I could swear it says "on a defense, if you roll a blank Fett's jet pack misfires and he falls into a Sarlacc pit and dies. Because he is Boba Fett"
Except it's been confirmed he never died there.