He can't not break Mary out of her tower.
Technically, this is some kind of treason, though Bash doesn't really stop to think what kind of treason. There's a world of a difference between betraying his brother and betraying the Dauphin. In fact, this is the difference between life and death, but he'd do it anyway, so why waste time on fruitless deliberations?
Sleeping with her is a different kind of treason.
Bash doesn't speak much of English. Just a few phrases he picked up here and there when he was no more than a curious kid. They might've been enough to eavesdrop on English envoys' servants telling each other bawdy jokes, but they do nothing to prepare him for the harsh sounds of Scots that surrounds him now. He feels slightly overwhelmed by the avalanche of strange vowels. Having lived in France his whole life, he isn't used to listening and not understanding, so he tries not to think about it, and focuses on doing what he does best: he keeps his eyes wide open, and watches his queen.
Mary has been quiet ever since they left her prison, barely saying a word on their crazy ride towards the shore. On the ship, surrounded by her subjects, her voice comes back strong and sure, every vowel more regal than the other until Bash can't take his eyes off her.
When she walks into his quarters on the ship, her face determined, he doesn't ask why.
He drops on one knee, and bows his head.
“My queen,” he says clumsily, his intonation all wrong. It's the only Scots phrase he knows, but it's been ringing in his head ever since he set foot on this ship, repeated endlessly by everyone around him until it's all he can hear, my queen, my queen, my queen.
“Je ne suis pas ta reine,” says Mary with a smile, but then their eyes meet, and she stops mid-word, hit by a thought, or maybe a memory, something he can't know or guess, and maybe he shouldn't.
Because Mary says a few soft words in Scots, and points at his bed.
This isn't the first time they end up in bed, it's not second nor third, but it's the first time Bash doesn't have even the slightest sense of treason.
“My queen,” he repeats standing up, the only two words he knows hanging between them like a promise.
(The only two words he needs.)
Mary's gown falls to the floor, and only then she reaches to kiss him hungrily. Tension and anger that have been marking her face ever since their escape are gone now, replaced by determination and will, but there's also a hint of softness that's neither regal nor girlish, but simply Mary.
She guides Bash's hands with patience, filling his head with Scots words until he forgets his French, fester, caur, God. His shirt lands on the floor right next to Mary's gown, and there is a moment of hesitation when she seems to be unsure what she wants next, so he presses his lips to her wrist, because he has no idea how to say let me.
Her breath catches at his touch, and just like that, decision is made.
Her knee bends lovingly over his shoulder, but she doesn't slide her fingers into his hair the way she always does. She's words, all words, foreign vowels melting into gasps of pleasure until they become familiar, guid, ay, belive.
By the time she comes, he understands them all.