Don’t give away the secret of this J.J. Abrams production, which begins as one sort of movie before turning into another sort of movie but manages to be continuously bad. A woman fleeing a troubled relationship (Mary Elizabeth Winstead) spins out in her car, flies off the road, and awakes in a sealed bunker presided over by a retired military man (John Goodman at his most sinister). He insists that he’s rescued her from what could only have been a nuclear or chemical terror attack outside, which introduces a welcome ambiguity into the dull, PG-13 Saw sequel that follows. A plot twist reveals that this is actually a sequel to a different film; that’s what constitutes a surprise in Hollywood entertainment these days. Dan Trachtenberg directed; with John Gallagher Jr.