While leaving the manor's lobby as Carnby, a FMV sequence will play when you meet Edenshaw. In the sequence, he will give you a charm of saving. Quickly save the game when the FMV sequence completes. Keep saving the game repeatedly to get four save uses each time.
At the start, had left until you find a building. Enter it, and a man with one arm missing will be sitting inside. Speak to him and get the key from him. Go back out and keep going. After you start walking a short distance, you will hear gunshots. Turn around and go back in the building to find that the man is now missing.