Well, if you get caught doing this, it will look like an admission of guilt, but there's one pretty surefire way to pass a lie-detector.

Take a strip of masking tape and punch a few flat-based thumbtacks through it so the spikes are sticking out of the non-sticky side. Then stick the strip of tape to the bottom of the inside of your shoe. Step into the shoe and await pain. If you've got those thumbtacks jabbing into your foot the entire time you're answering their questions, you're going to be too pre-occupied with the pain to be nervous about answering the questions correctly, and therefore, your test will show you as telling the truth.

Ask the other three guys if anybody checked them or patted them down for their tests. If nobody checked them before the test, and you're seriously scared of failing it, that's always a last resort option.