"Attempt to administer drugs to wrong patient"

I am very dissatisfied at the lack of friendliness and communication in the A & E Department. I know it is a very busy Department but patients are admitted then left for hours on end without any attempt to let you know what and when would be going on. A nurse entered the cubicle with some medication, she said to my husband that you can take these painkillers then you can go. I was a bit took back and questioned her about going home. She said hadn't we had a letter off the doctor, I told her we hadn't seen anyone. She then asked my husband his name to which she found out it was the wrong patient. I promptly told my husband to spit the tablet out of his mouth. No word of apology or anything. My husband who is an active cancer patient was admitted at approx 5.30 to 6pm last night with dehydration. He was finally admitted to CDU approx 10.15pm into a side room with barrier nursing notice on the door. As I left my husband for the evening approx 10.45pm, as I was walking out of the ward, I turned back towards the room and promptly saw a doctor from A & E casually enter my husband's room with bags of fluid in her hands without any barrier screening. What does that notice on the door mean?