At 10 : 59 AM the last element of the 2nd Battalion 4th Marines left the zone and the last naval helicopter landed at 12 : 15 on the USS `` Okinawa '' .
At 10 : 59 , the last element of 2nd Battalion 4th Marines left the zone and the last marine helicopter landed on the USS `` Okinawa '' at 12 : 15 .