Clock/Time question

[Jurassic Referee]

BillyMac would have done this eventually....

5.6 SITUATION: A1 is fouled in the act of shooting by B1. A1's try or tap is successful to make the score with team A leading 62-58. When the foul occurs, the clock is stopped with 0:00 showing, but no end-of-period signal (horn or light) has indicated.
RULING: A1 will attempt the free throw with the lane spaces occupied as required. The fourth period time has not expired until the period-ending signal.

As I said, that test question evolved from this case play and has been used several times already iirc.