Sorry, by apparatus I mean any method of observing a large body of matter or space that exhibit quantum behaviour (i.e. anything), not necessarily a physical machine. We are just looking for a series of highly improbable quantum state transitions.
Think of each observer attempting to push a rock into their palm and having it appear on the other side, without enough force to push it through. Think of everyone on the planet attempting this simultaneously, thousands of times. If the rock disappears and reappears on the other side for one observer, doesn't this accomplish the same thing, at least for that observer, that the suicide attempt does?
Failed suicide attempt is unlikely and provides evidence towards many worlds as a theory and not just interpretation.