So, recently I've been told that "Die in a Fire" is being sung through the animatronics' perspective, which was weird to me, since I had always thought it was being told through William Afton's perspective. But the more I thought about it, the more I realized how much better the song fits William than the animatronics. And so, I've put the lyrics down below, along with a description on why I think William is the one talking in the song:

I really hate you, stop getting in my way
I've lost my patience, when are you gonna decay?
(He's talking about the animatronics getting in the way of his plans)
I want to throw you out just like my broken TV
(Why would an animatronic have a tv?)
If you come back once more, it shall be painful, you'll see

I hope you die in a fire
Hope you'll be stabbed in the heart
Hope you'll get shot and expire
Hope you'll be taken apart
Hope this is what you desire
(He's talking about what he wants to do to the animatronics)

It's almost over, why can't you just let it fly?
(Him telling the animatronics to just let him win)
Don't be afraid, it's not the first time you'll die
(The missing kids, obviously)
Your mechanical parts click, sounds like when I broke your bones
(William probably would have had to break a few things to fit the kids into the suits)
Once I get my second chance, I won't leave you alone, oh yeah
(William's "2nd chance" is him coming back to the restaurant to demolish the animatronics)

*Chorus again :)*

This is just my interpretation of the song, so lemme know if you guys thought the same thing!