The Hollow Hour

Mason Cross stopped bleeding people eight years ago. Then the ground opened. A subway car flips. Concrete seals the exits. The air inside becomes a clock. Six survivors. One of them is already bleeding out. Another is starting to hyperventilate. Mason knows what happens next-panic eats oxygen faster than any wound. He also knows the ceiling crack is widening. Slowly. Too slowly. There are two ways out of this grave.
One requires a miracle. The other requires Mason to do what he swore he'd never do again.