There'd have to be a comedic break and a comment on how heavy big tits are, or you'll have the soccer moms on your ass.
Maybe she slyly pumps them up to unreasonable size just to topple over?
But I think having a sequence where she inflates them is too close attention in itself.
How about she turns up and has them visibly but not absurdly enlarged so Bruno asks her about it. Then he looks away for whatever reason and they're normal size again with her insisting they are perfectly fine the way they are and where is he looking anyway?