At their last meal together Jesus told the disciples that one of them was going to betray him (Mt 26:20-21). The disciples knew that the Jews were seeking an opportunity to catch Jesus away from the crowds (John 11:57). So when Jesus said this the disciples were in shock that one of them would betray him (Mt 26:22).
Judas must have been squirming in his skin. Everyone was saying, "Lord, is it I?" It would look suspicious if he didn't ask. But if he did, and Jesus exposed him to the rest of the disciples, what would they do to him? Still he might escape their outrage and make it to the Chief Priests. So he asked, "Rabbi, is it I?" (Mt 26:25). Jesus responded, "You have said it."
Judas must have felt as though every eye was on him, but it was as if the other disciples were deaf. They all were still were too absorbed in their own fears of betraying him. So Judas immediately left unscathed (John 13:26-31).
It is possible to fool others, but it is never possible to fool God.
