Why is the killer in Bridge season 3 shown appearing to have a revelation about the killings

Why is there a scene showing the killer, Emil Larson, appearing to have a revelation about the connection between the killings and works of art being exhibited in the gallery where he is employed? He is not being watched, so he is not pretending to discover this for any possible observer's benefit. It makes no sense given that he is the killer and obviously knows all about the link.