truly, the mech pilot is a creature faced with a dreadful proposition: your boss is your most reliable drinking buddy.
There are so many honestly enjoyable (or at tolerable) mecha anime that would be improved and/or completely different if the setups were exactly the same but the characters were aged up to drinking/smoking age.
(this is not necessarily me doing the misguided "i want this thing for teens made for olds like me instead" but rather i think it would be funny and interesting if no anime teen could ever make the "but i'm a minor" joke ever again when spoken to by a grownup)
it's honestly such a great encounter to think about. Here the young mech pilot is, imbibing alcohol as a sign that they are stumbling into the demands of adulthood and thus are entitled to it's vices. They struggle to comport themself, perhaps embarrassing themself or locking it down in the final moment. The Boss is the gatekeeper of maturity, though this is a great opportunity to turn this on it's head. While they can at this moment, let the mech pilot pass this moment reflects on them as well. Slowly we descend on a matrix of characterization just in how these two characters behave over a drink, coordinated entirely by a power dynamic and the socialization surrounding alcohol.