You after reading this chapter a few times I recall that there's usually security cameras in hallway in hospital.
Won't the person watching the camera a night thinks that mieruko is hallucinating by running around the hospital and hiding in random corners and such.
They probably even though that Rom is a therapist doctor calming her down and lead her back to her room.
It also probably doesn't help when the old man ghost and his family moved on she is always in front of Rom like a doctor humoring a patience so they would go back to their room.