On the second floor in the lounge, there is a storage room. When the lounge is empty you can go to the storage room and get a tool from the toolbox on the top shelf. You will need to go grab a stool from the lounge to reach the toolbox.
Afterwards you can use this tool to break a red pipe in the maintenance room, this will cause some flooding and allow you to sneak up to the third floor and talk to him.