Psychiatric ward

Back when I was finishing my college studies in computer science, I had been assigned for training in the city's hospital for 12 weeks in order to obtain my college degree. The first task they assigned me was to do some configuration modifications on all computers in the building to prepare for a massive network fusion with all governemental healthcare facilities of the same district.

So there I was left with a huge pile of papers listing the location of every office which had one or more computers that needed to be configured, ready to go explore the place.

Although the task itself was rather repetitive, I was thrilled about having to explore every single corner of the hospital like a VIP employee; that meant heavy security intensive care sections as well as high-contamination-risks biology and genetics laboratories (which made the self-proclamed mad scientist in me restless and exceedingly excited), the heartwarming nursery, and... the scealed off psychiatric department.

The very first time I set foot out of the elevator in that department sent chills down my spine. The whole floor was blinding white all around, empty, with nothing but a large wall with a single heavy metal door and no windows. According to my papers, the psychiatric section was behind that door. There was not a sound to be heard -not even ventilation- nor an employee to be seen passing by.
I started walking toward the door and stopped as I began hearing a faint but familiar sound: a single piano note repeated over and over again at regular intervals. I looked at my papers again and noticed I had missed the gynecology section. Relieved, I ran out of the place to finish off the day elsewhere less creepy.

The following day, I had to go back for it was the last department left in need of configurations, and this is what I did first in the morning, for I would be out of there sooner.

I went back up and was greeted by the same opressive silence and deathly white surroundings. I walked to the door, but no faint piano sounds this time, fortunately.
I pressed the security button so an employee would unlock the door, which they did pretty fast, and stepped in. Corridors seemed as lifeless as the outside. No employee to be seen anywhere, though the silence had been replaced by loud and squeaky ventilation noise. I only had 4 or 5 computers to configure in the area, and since most offices were empty with lights off... and a wide open door, I deceided it'd be faster just to sneak in quietly and quickly apply the modifications than try to find someone to inform and ask permission. Those weren't changes that employees would notice anyways.

The last office, however, was locked. I knocked on the door and waited. Nobody came, but as I was about to give up and leave -intending on telling my superiors about the office I couldn't access-, the door finally opened. A mid-aged lady greeted me with a large, but empty -and nearly crazed- smile and a friendly but mechanical "Hi! My I help you with something, dear?".
I jumped back out of sheer surprise and as calmly as possible explained to her what I was there for and she let me in. The whole time I was working on her computer, she just stood there... watching me with the same unfaded grin on her face. I glanced back at her a few time, disguising my moves with either a forced smile or an "I'm almost done. You won't see the changes, don't worry.". She never replied nor moved. She just stood there, forever smiling.

Once I finished applying the changes, I left the office... and with the same mechanical friendly speech, she thanked me and watched me walk down the corridor until out of her sight. I leaned on the wall, trying to digest the unnerving atmosphere of the place I was in and that woman's attitude, when I heard the repetitive piano notes again. This time more curious than creeped out, and having finished my job earlier than expected, I chose to follow the sound to see where it came from. I followed it up to a wall with large windows further down the corridor and as I came closer to the window, I herd a mad agony scream (though well muffled down by the thickness of the wall). I ran to the window... just to find out the room was empty and lifeless, with its lights closed...

...and a well broken down piano that probably couldn't produce a sound.