Mal wasn't stupid, neither was he keen about not having his two feet on the floor of his ship right now. That location would have done wonders for his amount of authority right now. While being in the hospital and having Kaylee to look after might keep him mindful of his actions, he still had one more mouthful of words for the delicate doctor.
"No, you ain't the boy.." And did he ever stress that word. "... I let on my ship. Now that your sister don't need you, a martyr-type like yourself must be desperate for someone to pat you on the head an' tell you how much 'good work' you do."
Mal moved forward a step towards Simon, a faux-check -- just to see him startle. Then Mal turned away to return to the door of Kaylee's exam room. "You don't have to be on my ship to be on my crew, but those are two specifics you don't have to worry yourself with." An angry fist wrapped around the doorknob, twisting it open to allow himself back into the room, shutting it quickly behind him.