"We want to get the check."
"Get the check" is both very American, and ambiguous in this context.
The more obvious is that in a group of people, a couple of the people are offering to pay for everyone else. The other, which I'm guessing was intended, is that the people who just ate are asking the staff in an awkward style if they can now pay the bill.
Is the Chinese ambiguous in this way? If not I suggest going to a more natural English wording.
The Chinese sentence is not ambiguous. However it is only good for saying to a waiter but not a friend.
This is a way of speaking imported from Cantonese, not the traditional one in Mandarin. Not that you can't use it in real life, but just don't analyse it as "buying the bill".