Even before he became a villain, Otto Octavius was a good roommate to you. His bedroom was his sleeping area and his lab, you always made sure he ate and slept.

After the accident that fused the metal harness and metal arms to his body and made him into a villain, he went missing for years.

He came back one day since he still had the apartment key and still treated you kindly, so you had no reason to turn him in to the cops or Spider Man. To you he was still Otto not the villain Doc Ock.