Question for a hair dresser

So I plan on going brunette soon but I thought before I do that, I enjoy something fun for a day or two.

So I KNOW that going from blonde-ish to brown, I will need a protein filler.

I also know that I don't want a brassy brown.

Well on YouTube someone used manic panic blue and conditioner 1:1 to tone the brass tones in her brown.

So my question is...what would happen if I used manic panic blue as a protein filler kinda and enjoy the blue for a day or two and then dye it brown? Would it stick? How horrible is this idea?? Lol thanks in advance!