This video shows you how to do the Safety Drop Glitch (also Safety Drop Bug).

This video was made in Tomb Raider I: Unfinished Business, in the Level Temple of the Cat and shows you how you can drop down to the third secret without loosing any health.

This glitch works in all classic games. It enables you to reach a lower platform where Lara can not drop from ledge to ledge, because the drop is too far; or to reach the floor avoiding a trap underneath the drop (like the spike pit in Colosseum, Tomb Raider I).