It was the way of Rabbi Menachem Mendel of Kossov to lead the congregation in prayer himself. In the synagogue there was a screen between him and the people, who would hear his clear and sweet voice, and they too would direct their hearts to pray with love and fear of God in a sweet way. And no one would ever dare to look over the screen into the holy place during the time of prayer.
But once someone lifted himself up on the wall of the screen to look over, and was startled and jumped back, falling on the ground. He lay there like a stone in a faint, and only with difficulty did they bring him to. Upon regaining consciousness, he told them that he saw the holy Rabbi fully prostrate on the ground and a fire was blazing all around him as if he were an angel of God; and that was why when he looked he was stricken and fainted. (Even Shetiah, pg.22)