Jerrod Carmichael makes his directorial debut and stars in “On the Count of Three,” a darkly comic feature about two best friends, Val (Carmichael) and Kevin (Christopher Abbott), on the last day of their lives. Val has reached a place where he feels the only way out is to end things. But he considers himself a bit of a failure—his effectiveness lacking—so he figures he could use some help. As luck would have it, Val’s best friend, Kevin, is recovering from a failed suicide attempt, so he seems like the perfect partner for executing this double suicide plan. But before they go, they have some unfinished business to attend to.