NFL rules question

[dolphins4life]

Team A has the ball with ten seconds left in the game.  The score is tied.  The pass is intercepted and Team B runs the ball back to midfield as the clock expires.  However, in tackling Team B's player, Team A grabs the facemask, and is called for a fifteen yard penalty.

Does the game end there, or is the penalty assessed and Team B gets one untimed down from Team A's 35?

[Spider-Dan]

Team B gets one untimed down from A's 35.

[Pappy13]

The game can't end on what amounts to a defensive penalty.

[MyGodWearsAHoodie]

It would B coaches decision to accept the penalty or not.  If the penalty is declined the game would enter overtime.  In no situation would that be the final play.  (Any coach 0€to decline the penalty rather than attempt a FG would likely be fired the next day.)