In the movie "Rollercoaster", they don't have the element that they can't stop it, atleast I don't remember. Are you talking about the part on revolution, where the bomb is planted under the seat. nd the guys disarm it or get the guy before the bomb goes off? If so, its "Rollercoaster"
Nice tricky thread title, though. ;)
The Flying Turns makes all the right people wet - Gonch
The movie you´re looking for is most probably "Thrill!"