A thought I considered as the film progressed.

If the penthouse owner enjoys strange art as much as it seems from the chosen paintings on his walls, he may actually appreciate all the artwork that came out of Nemo (Dafoe) as he despaired and suffered in his stay at his temporary locked penthouse prison.

He may even get the walls removed and framed in order to keep his Artwork. It might hold value as it has some provenance of coming from the thief who stole million dollar artwork and escaped.