end of Oklahoma Iowa football game

Did anybody catch the end of the Oklahoma-Iowa State game? Let me say off the bat, that I had no betting interest in this game.

Trailing 42-35, Iowa State scored a TD with 24 second left. They opted to go for 2 point conversion and presumable win instead of tying the game by kicking an extra point. So the 2 point conversion pass was intercepted in the middle of the end zone (5 yards from the end line or back of end zone and 5 yards from the goal line). The intercepting player from Oklahoma, turned and made a beeline for the back of the end zone running out of the end zone.

Now it is my understanding that the play is not dead upon the interception. That is why teams sometimes run the two point conversion back for 2 points of their own. The play would have been dead if the intercepting player had been tackled, fallen to the ground on his own or even just taken a knee. But that act of intentionally running out of the back end zone, I believe should have resulted in a safety, according to how I understand the rule, which of course would have given Iowa the win.

Any thoughts?

edit correction: The rule book states that a safety occurring on a two point conversion is worth only 1 point rather than the 2 points that a safety in normally worth, so a safety can definitely occur during a two point conversion. 1 point...Who knew?

There have only been 2 occasions throughout college football that a 1 point safety was recorded on a two point conversion play. I believe based on intercepting the ball, establishing himself on the field and then intentionally choosing to run out of the back of the end zone, this should have been the third such occasion. If so, this would have tied the game and likely lead to overtime.