There are many ways to do Cliff Diving.
You can take emetic poison with you like in my video:
Emetic Rat Poison is on the Mansion Security guard that is in the camera room on the second floor.
And to everyone that said there was not, there IS a can of expired spaghetti sauce in the attic. It is all the way in the back on the right.
Bringing poison with you is the best bet.