Tony Elliott didn't know the rules of overtime, and it should have cost them a delay of game penalty, but it didn't, giving Florida State an unfair shot.
The rules for overtime are explained to the audience at home right before overtime starts. It seems pretty clear. The first overtime is normal; you score, you get to kick an extra point. However, in the second overtime, once a team scores a touchdown, they have to go for a two-point conversion, and every overtime after that is simply just two-point conversion tries until one team fails.