detect a third number of shock events in {HEAD ~ response} to {TAIL ~ the shock detector} operating at the increased shock threshold; and 
to
detect a third number of shock events in { HEAD ~ response } to { TAIL ~ the shock detector } operating at the increased shock threshold ; and
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH