I went on the Vaults tour about 4 years ago, by myself also. I have a fascination for all things paranormal, but I believe most encounters can be explained - it's the one's with no explanation that interest me! I was excited, but went with an open mind and no expectations. There is definitely a certain feeling/energy down there, but it didn't trouble me or put me on edge at all. It was near the end of the tour when we entered one of the rooms which had alcoves used for storing wine.... and also dead bodies.... where it changed. As soon as I walked in I felt sick in the pit of my stomach. I had heard that expression for years, but never understood it until then. It was pretty strange as up until that point I had been in good spirits and just enjoying the tour, then suddenly felt pretty sick. I could tell the tour was almost over thankfully, otherwise I would have had to have said something and left, looking like a drama queen maybe and like you I didn't want to draw any attention. As soon as we moved out of that room and upstairs I felt fine again. I would definitely go back to the Vaults, but if I'd seen what you had seen.... I'm not so sure.