The hall was too bright for him to turn the wall or door invisible, meaning his only recourse was to send Painted Black directly into the room - No, from this angle those girls were able to see his shadow, meaning that if it moved in a way that wasn't natural one of them might notice, which could cause problems . Therefore the best approach for him to take would be to cause some kind of distraction, and move Painted Black inside the room…

"Am I really that interesting?" he asked the girls, turning towards them, and moving to lean against the side of the wall. Perfect, they wouldn't be able to see his shadow from here! He sent it inside the room. No sign of her. So where was she? "You girls must have better things to do than stare in wonder at council related business. Right?"

-Lulu's Bizarre Rebellion Chapter 35