Character mistake: After Dimitri put Leena's wrist bands on for her (through the door slot), Leena said, "I want to do something nice for you; you can come in." Dimitri agreed, and Leena pulled up a chair to stand on (to be his height) and caress his face/ hair. When Leena bent in to kiss him, she banged his head against the wall several times, killing him. As a "Saarne Instituute" security member, Dimitri should know not to get sexually involved with or trust a patient, especially the most dangerous one. (00:10:29 - 00:11:29)
Character mistake: Miles is playing on the beach a tune that Birdie Jay recognizes instantly as Blackbird by the Beatles, and Miles flexes saying that it's the exact guitar Paul wrote it on. That'd be difficult though, since it's a right handed guitar, and McCartney plays left handed (albeit he can play right handed too). You could argue that this is one of the hints that Miles is not very smart. (00:20:00)
Character mistake: "Joker" announced, "we get out of our cages once a week for one reason only. And that is, The Dungeon [where the fights are held]." The cells were in PODS, where the inmates hung out. Inmates had work assignments around the prison and walked the halls. There were outdoor exercize areas with gym equipment and basketball hoops. There was a pool table, games, TV screens, a common cafeteria, etc. - far from "getting out of cages once a week." (00:36:50)