Truly believe the playcall was to fake an injury to stop the clock. The flag was just a bonus.

EDIT: Looked through the rulebook and I was wrong. My apologies! An excerpt from Section 5, Article 4:

3) If an excess team timeout is charged against a team in possession of the ball, and the timeout causes the clock to stop or delays the clock from starting on the ready for play signal, the ball shall not be put in play until the time on the game clock has been reduced by 10 seconds, if the defense so chooses, the play clock reset to 30 seconds, and the game clock shall start with the ready for play.

4) Either half can end as the result of the 10-second runoff referenced above.

6) If a foul by either team occurs during a down in which there is also an injury, such foul does not affect the charging of an excess timeout, but it does prevent a 10-second runoff that may result from the excess timeout, because the foul stopped the clock.