His predecessor Daniel Marx, Mr Cavallo's deputy who resigned last Friday, is also reportedly waiting for a tap on the shoulder.

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The most common incidents -- the slam of a door, a car backfiring, a surprise tap on the shoulder -- can cause a panic reaction.

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And where there is power and money behind that dark hand, therefore, a lot of attention is paid to that little tap on the shoulder.

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As I hung up with the third failed attempt to get a car I felt a light tap on my shoulder.

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