This happened to me once while I was working with an agency nurse. I asked her to pull the blue cord and instead she pushed the blue button. I Immediately started laughing, thinking she got it half right!! Luckily, at the time we had this little old lady who found out a great way to get lots of attention was to walk into patients rooms and press the code button so Instead of actually calling the code they called the floor to ask if she was up to her old tricks. No harm, no foul!