It depends. First, I'm assuming that all these shenanigans are legal.
Second assumption is that if I don't take the job, someone else will. So, no matter what, kids are going to die in droves from this advertisement, regardless of who's behind the wheel.
If neither of these conditions are met, then my answer is "hell no". I doubt I'd be able to kill one person for 2 million if that death is avoidable. Not in good conscience, at least.
If the above conditions are met, then I'd donate 1-1.5 million a year towards cancer research. 2 million is an absurd amount, I don't need that much, at all. I think 500k would be sufficient for my purposes. 1 million if it's not a longterm job. I don't WANT to live in a mansion with a hundred-thousand dollar car or any of that crap. I'll be able to live comfortably, help cancer sufferers and rationalise my own role in the proliferation of cancer with an "if not me, then someone else, and that someone else would just keep the 2mil" mentality.
I'd vastly prefer that the entire ad campaign not go through, though. But if it's inevitable, I'd do my best to mitigate the effects.
Also, a little food for thought for those taking the "nobody pays attention to ads anyway" route: Why, then, is advertisement such a massive industry? In a world where the corporations doing the advertisement will do anything legal, and some that's not, to min/max their costs/profits?