Corrected entry: SPOILER ALERT: When the Joker kills his mom in the hospital, the heart monitor that she is connected to does not alarm as her heart rate skyrockets, then starts to fail. This would cause the nurses to come running into the room. Setting an alarm on the heart monitor is standard medical protocol in a hospital, especially in an ICU which is where she would have been with her serious condition.
odelphi
22nd Oct 2019
Correction: He could have switched it off. Not the monitor but the alarm. He had all afternoon in her room to figure out how.
lionhead