Even outside the tackle box, the ball has to cross the line of scrimmage.
Rule 7-3-2 (h)
The forward passer, to conserve yardage, throws the ball forward into an area where there is no eligible Team A receiver (A.R. 7-3-2:I) [Exception: If the forward passer is or has been outside the tackle box, he may throw the ball so that it crosses or lands beyond the neutral zone or neutral zone extended (Rule 2-19-3) or would have crossed the neutral zone if not touched by Team B. (A.R. 7-3-2:VIII-X) This applies only to the player who controls the snap or the resulting backward pass and does not relinquish possession to another player before throwing the forward pass.]
(Edit). Just watched the play again, LOS is the 6. After Banks throws it, the ball lands about where the 9 yard line would extend out right before the wall. Should have been intentional grounding and forced a 10 second runoff. Tulane shouldn't have gotten those 3 points.
3 plays earlier was also where the Tulane receiver caught the runner and dragged him forward 3 yards with no call. Next two plays are where Oliver gets tackled and then mauled. They finally called a penalty on the false start at the goalline and then the play that should have been intentional grounding happened.