If the substitution takes more than 25 seconds, a flag could be thrown for DOG, but that gives the offense what it needed, additional time to run another play. If the delay in getting back to play is judged by the referee to be for the purpose of consuming time or conserving time, he can order the clock to start on the ready. If the officials believe the loss of a helmet was intentional, the referee can just run the clock out. This type of activity is discussed in the case book at 3.4.6.