[Oh. Well that explains that, then. For some reason, though, Kokichi's words seem to cause some kind of connection in Shuichi's mind. There's definitely a lightbulb turning on in there.]

Decoys... [He mutters the word to himself with a thoughtful sort of frown.] Oma-kun...there are two other spots like this... I didn't realize it until you mentioned pressure plates but...this might not even be the actual entrance...it could just be a fake, meant to confuse...