Vanishing man seen in the Slate Bedroom

I was told a fascinating story last week, which I hope to confirm with the Room Guide who experienced it. I was told by two of the conservation team that a volunteer Room Guide was standing in the corridor looking into the Nursery bedroom last week, when out of the corner of her eye she saw a man in a dark jacket walk into the Slate Bedroom. She quickly went into the room expecting to see a visitor standing there but she found nobody in the room. She looked all around the room and even looked under the bed in case he was hiding there! She could not think where he had disappeared to. She looked down the stairs towards the Grand Hall Gallery and opened the doors to look up and down the spiral stairs to the other floors of the Keep. He had completely disappeared and yet he had seemed so real. I look forward to reading or hearing the account from the lady who had this experience and will update this account when further details are told to me! It would be interesting to identify the man if possible.

Has anyone else seen anything in this area of the castle? Please let me know. Thanks.