his imagination provided him with an answer in the form of a sudden indelible image : hundreds of people failing out of the sky , ties and trousers rippling , dresses skating up to reveal garter-belts and underwear , shoes falling off , pens ( the ones which were n't back on the plane , that was ) shooting out of pockets ; people waving their arms and legs and trying to scream in the thin air ; people who had left wallets , purses , pocket-change , and , in at least one case , a pacemaker implant , behind .