From inside his jacket pocket, John produced a small metal flask, silver in apperance, with a magical seal engraved on the side. It was there purify poisons in the off chance someone tried to spike his personal belongings. Of course, it meant not very much could go into the flask. Whiskey, Gin and Absinthe could go into the flask but not much else.
"Tell you what, I'll ask the questions and you give me the answers, and you can have a drink from this" he said, giving the flask a small shake to prove there was indeed liquid inside. "It's Whiskey. The good stuff" he added. "And plenty more where it came from if you're cooperative". It was true, he had more. But he probably wasn't going to share it. John may have been a talented magician but his true art lay in the con.