Maybe he was scared of all the traffic showing up in the area so soon, hid in those woods, then called for someone close to him, to come pick him up near that building which he could see from his hiding place. Maybe he and his "ride" then went and picked up his vehicle parked in the area, possibly at the Cemetary ?....mooIt's mind boggling to be honest.
The family and LE were out searching so quickly.
Either the attack was over really quickly and BG got the hell out of there as fast as he could (even then he was lucky not to be seen in the act) or he took them somewhere where he could spend time doing whatever he did then moved them after (but why not leave them in a place he took them rather than risk moving them).
Search parties were all over that site within an hour or so! It does not make sense to me, I appreciate the area is vast but honestly how he was not caught in the act puzzles me.