If you've played 5 times already, then you should already know better than to let your alignment dictates you. v=3=v
(Seriously even in the 80s people have already had problems with this exact thing. in 2020s you should already know better going in. Especially in 5E where this is supposedly minimalized.
Not saying if actually unreasonable things came up you should also follow that, but in cases like this it's a two choices thing:
Either you:
1) Rethink and come up with a way to keep things going. Or,
2) Follow an "ideal" that nobody but you - even outside of your table - understand or care, and Deadstop the whole game and f__k everyone up for pretty much no reason.
If you pick 2, I would suggest that the door's just a few steps to your side.)
Reminds me of a long time ago in somebody else's group there was that one guy who up and murdered the quest giver king on scene 1 "because he's Chaotic Evil"

They talked, and the GM did a rollback, and then things kept going.
Didn't expect I'd run into the same thing after 20 years... !!!=w=