That's the point of the game. You have to try to make guesses that will inform what's going on with both words at the same time, while reserving two gases to actually fill in the correct answers once you figure them out.  If my opening word has to correct letters on the right and none on the left, then I'll spend my next guest trying to guess some more correct letters for the left. Once the left has three and the right only has two that I might try to fill in some more letters on the right, etc