Bruce Willis was dead the whole time.
When we were in writing school, Adam Peterson and I wrote a bunch of paragraphs together. We called them "chunks." At the top of each chunk were the words "[SPOILER ALERT]."
Is this a gimmick? one of us said.
Probably, said the other.
Are we making a book? one of us said.
What's a book? said the other.
And thus, [SPOILER ALERT] was born.