Reaching the boy, the woman carefully takes hold of the boy and starts to squeeze, gently at first and then ever more firmly. After a few seconds the boy convulses violently and coughs up the quarter, which the woman deftly catches in her free hand. Releasing the boy, the woman hands the coin to the father and walks back to her seat in the coffee bar without saying a word.
As soon as he is sure that his son has suffered no lasting ill effects, the father rushes over to the woman and starts thanking her saying, "I've never seen anybody do anything like that before, it was fantastic. Are you a doctor?"
"No," the woman replies. "I work for the IRS"