Right, first things first, on no account is anyone to try this at home.
Quantum Suicide is a thought experiment based on the Many Worlds Interpretation of quantum theory. According to the interpretation, every event in spacetime causes the universe to split into different versions of itself, containing every possible outcome - essentially, parallel universes - in a process called decoherence.
Quantum Suicide is essentially the Schrödinger's Cat experiment from the cat's point of views and the theory suggests that it is possible to survive one's own suicide. The reasoning is that, in a situation in which the two possible outcomes are survive and perish, the subject would only ever be aware of the "parallel universes" in which they survived.
It is, however, probably not worth the risk.