4.2.2  How do I get to the timed door at the end?

            There's really no "trick" to finishing.  You just have to
            drive faster and steer without hitting anything.

            There is, however, a trick that you can employ, which was
            meant for the case you don't have the boat at all.  Take
            the boat and leave it outside of the room with the button
            that opens the double doors.  Swim into that room and push
            the button, which closes the door and opens the door in
            the clock tower.  Stay away from the little ramp, which
            would start the counter,  but rather swim underneath the
            door and now you can take your sweet time to finish the
            level.