Extended Period Mechanics (NFHS)

[Suudy]

While working through our association test for this fall, one of the questions prompted me to think of the mechanics when dealing with a foul on the last timed down.

1st and 10 from A's 20. Clock stopped. A1 runs to the A 25 where he is tackled inbounds with 5 seconds left in the period. During the run, B1 twists and pulls A1's face mask.

So, we stop the clock, enforce the penalty, and we have 1st and 10 from A's 40. The clock starts on the ready. If time expires, we extend the period for one untimed down.

So, my question with regard to mechanics is if A rushes to the line to try and get the play off, and time expires before they do so, do you blow it dead, declare the one untimed down, and have them reset? Or do you just let things go and ignore the time expiration?

(Depend on whether management has turned off the scoreboard buzzer or not, this may be different.)