Plot hole: There is no way that Malcolm would have been able to write that message on his stomach. He gets found by the nurse and then we see him in a room getting some medicine and then he is in the operating room.
Suggested correction: Actually before is given some type of sedation before the surgery he is wearing a different hospital gown. He would have had enough time to write the message on his stomach when he was asked to change into the blue gown.
Helmut was afraid Malcolm would run off again, so he likely changed him into the blue hospital gown after he tied him up to the bed. Malcolm could not scribble the message if his entire body was restrained. In the operating room we see he cannot move due to the injection Helmet gave him which eliminates the possibility of him writing the note here. Malcolm probably convinced the doctor who ran the blood test to have one of the surgeons secretly write the note after they prepped him in the OR.
