Ok I realy think I can almost perfectly analyze this song because I'm also a vocalist in a rock band and I've written a song almost exactly like this from a time in my life and I wrote it before I heard this. Anyway this is talking about suicide. My assumption would be that M. Shadows is someone who, like myself, believes in God, but yet wants to live his own life. He finally cannot take it anymore, and he therefore chooses to make peace with his maker and end his life; therefore he would know he was forgiven when he died. He asks for the brompton cocktail so he can go out happy. He explains this when he talks about believing that he's been forgiven, and he says, "please don't question why I left this way" I may be wrong, but I find it much too similar to my song when I contemplated suicide and wanted to make peace with my maker and od.