For a few seconds, the knight remained silent. He looked pathetic and pitiful, arousing feelings of sympathy in many who watched. Lex, of course, felt nothing, because, as Z said earlier, it's the teacher with the badass eye technique who was the coolest anime character.
While Lex was not an anime character, he did have eye techniques. To be specific, his left eye could see through everything, from laws to affinities to anything else in between, and his right eye could create, whether it was through arrays, or Glyphs, formations or anything else.
He had even unlocked Karmic vision, though Lex was incredibly careful about how he used that after Jack started to stink.
The point was, with his left eye, he could see through the Dark Knight. While it was entirely true that he was affected by Lex's revelations, it was also true that he was subtly using some technique with his armor to arouse sympathy in those around him, and lower their guard.
