he went through the sequence again : finalize calibrations to ensure accuracy of sight , await the signalthree rapid knocks on the door , most likely about fifteen or twenty minutes into the lecture ( he had no idea what the criteria were for the final go-ahead , but this was not for him to query ) , make any last second re-calibration if conditions have changed , fire the shot , collect the bullet casing , withdraw into the room , dismantle rifle and return to its canvas bag , dismantle tripod and return to its canvas bag , scan room to make sure no trace of his presence left behind , leave by the back stairs , enter the gray van idling outside the back entrance through the tail doors which will stand slightly open , hand the two canvas bags to the guard in the back of the van , travel with him for approximately five minutes , exit the van and get in the light-blue volkswagen with stuttgart plates waiting there ( the driver will have a green woolen cap ) , drive to unknown but safe location and lie low there until the wind dies down , a few weeks or so .