In "Angela's Ashes," why did the nuns move Frank to another room?

Frank catches typhoid fever and ends up in the hospital.  He has his own room, and very few visitors.  While there, the girl in the room next door begins talking to him through the wall.  She is Patricia Morgan, a very forward and stubborn young lady - also, incidentally, a very sick one.  She insists on talking to Frank, even after the nuns warn them both to keep quiet. 

Seamus, the janitor, brings books for the kids, and Patricia insists on reading through the wall.  Although Frank protests at the poetry she loves to read, she begins to read the Highwayman, and Frank gets sucked into the story.  At about the midpoint, the nuns catch on that they are still "chatting", and they move Frank upstairs to an old ward, where he is alone in his bed and not in the proximity of any other rooms.

Patricia dies shortly after.  Seamus, taking pity on Frank, alone and now grief-stricken at losing this friend, brings him the story of the Highwayman. 

Patricia is Frank's first female "interest."  Although he doesn't refer to her in the terms that he does when later taking about Teresa, it is clear that he is fond of her.  He thinks back on her often as he grows up.  This incident serves two purposes - it shows, through this "opposite sex relationship", that Frank is growing up; it also further underlines Frank's criticism of the Catholic church.  It was the strict and unrelenting narrow-mindedness of the nuns that oppressed both young people.