I'll have to agree with XCrusherX, that's exactly what I thought. "Don't put an end to your life 'cause that's where you showed your last sign". In this situation the singer's friend is planning to commit suicide, and he's telling him not to do it. Suicide also explains the name, Departure Plan. Someone who's planning to commit suicide is planning a departure from this world.
I'll have to agree with XCrusherX, that's exactly what I thought. "Don't put an end to your life 'cause that's where you showed your last sign". In this situation the singer's friend is planning to commit suicide, and he's telling him not to do it. Suicide also explains the name, Departure Plan. Someone who's planning to commit suicide is planning a departure from this world.