First you need to create a superstar, then edit his move of dash in create a move-set, then change one of the running grapple for DDT 3.
Then go to exhibition and play main events, and play hell in a cell and choose your created superstar and another superstar (note) you need to play your created superstar.
Then when you start to play wait until he is close and throw him into the ropes.
Then rapidly you run with him, when he is on the ropes do the DDT 3 and you will see that he will be out and he can not enter again, at least that you open the door.
If you do this trick wrong you will be out or both superstar will be out and The only (unique) way of entering serious the roof, good luck.