If you're playing the story mode, you don't need to tranquilize the lion (the tranquilizer is for the demon). You need to summon the demon by finding and destroying its favorite item.
Hi again! I got back on my computer to try it again just recently, and I realized that the key to the director's office might be bugged. To clarify, I'm not referring to the door that requires you to use the vent to get around; I'm talking about either or both of the two glass doors before that. I tried to use the key I found in the guard's room on both of them to no success. Is it a bug, or am I supposed to find that key elsewhere? Thanks!
Sorry for the delay in replying. The key in the guard's room opens the door to the service area (the door in the lion room). There seems to be a slight translation problem here.
As for the key to the director's room, it does exist, but it is not mandatory and is hidden in the locker room (it will be difficult to find).