He is shown to have more than a few quirks, such as eating his lunch on the autopsy tables - reasoning that the disinfectants used in the morgue are so powerful that the morgue is "the cleanest room in the city" - and always has a sarcastic remark. His diagnostic skills, however, are on a par with Lanie's, and they seem to share a mutual respect, if not a lot of screens time. Perlmutter frequently makes Castle the butt of his jokes or snide comments.