Learn English – To, in, at or into the Past

I think "go" here is an abbreviated version of "go together". "Go together" is an idiom meaning "are well-suited to each other", "are compatible", or "make a good pair". You might say, "This lamp and this chair go together" meaning that you think the styles of each are such that they are attractive when placed next to each other. We often say that two people "go together" meaning that we think that they make a good couple. (Perhaps I should clarify that we also say "those two people go together" meaning that they are involved in a dating relationship, which phrase, I think, has totally different origins but ends up being a closely-related idea. The two ideas go together. :-)

The word "go" can have other meanings that would fit here, like "work", as in, "Does this car go?" meaning, "Does it work correctly, does the engine run, etc.?" But the next sentence is "If they match", so I think the writer is stating the same idea in two different ways for emphasis, "If they go [together]. If they match."

Prisoners in the United States are, not surprisingly, prohibited alcohol. Prisoners are an enterprising lot, and they have found a great many ways to get around that prohibition, most notably via pruno, a homemade wine made by mixing anything fermentable (sugar, fruit, bread, ketchup) in a plastic bag and waiting a few days. The resulting alcoholic beverage is often hidden in the toilet.

In the movie, the boy who is worried says that he'll have to make root beer, a traditional (occasionally homemade) soda, in the toilet after he is arrested.