There are a few types of questions:

1. Indirect question: "Hey you, what would the other guard say, if I asked him where this door leads?" The answer is always negated.
2. Tricky question: "Hey you, does an honestant stand at the door to freedom?" The answer will be YES, if I am asking an honestant who is standing at the door to freedom, or if I am asking a swindlecant standing again at the same door. So I can walk through the door. A similar deduction can be made for negative answer.
3. Complicated question: "Hey you, what would you say, if I asked you ...?" An honestant is clear, but a swindlecant should lie. However, he is forced by the question to lie two times and thus speak the truth.