Would "We say goodbye before we go to Vietnam" work?
It's definitely correct English and a correct translation of this, so I can't see why not! (I've reported it)
I write such this answer too but wrong
how do you know if it's going to or going from (leaving)??? You need to have the preposition in there!
No, because to express leaving a place in vietnamese you wouldn't use đi = go (to is implied) somewhere, but rời = leave (a place)