GZ leaving the car was a reflex action - just like that of a dog or cat who, every day, jumps at the bowl of food you are carrying, even though you always put in down for them in a few seconds. If he thought about what he was doing, he would have realized that his best hope of sighting Martin again was to head down TTL in his truck where he could see both the other end of the dog path and the back entrance. It was totally illogical to try to keep him in sight on foot in a very dark area. As far as his gentle, timid nature, the challenge game he was in with Martin pumped up his adrenalin enough to cause a temporary personality change.