Maybe he was drunk and disoriented.
I think this is what probably happened. I understand why his family doesn't think that running into the woods is something he'd do...but this board is full of cases where someone does something that their family and friends swear they'd never do. And people do all kinds of out-of-character things when they've been drinking. (Which...I don't think any of the articles have specified if he was reportedly drinking or not, but...college guy, at a college party...chances are good that he was.)
The article neverletgo linked above says that "he could not tell the person where he lived" and then left the person's car. When I was college-aged, I had the experience of offering a drunk guy a ride home because I was trying to be nice and responsible...and then wasting an entire tank of gas driving around and around, and getting increasingly irritated in the process, because he was too drunk to know where he lived or how to get there, and much bitter arguing ensued. So I can see this happening in this case.
And when I was college-aged, there were also a couple of times that I hopped out of a car at a red light and then walked home because my date was getting handsy or otherwise pissing me off. In fact, once I went out on a first date double-date, and the guy upset me by sitting in the back of the car with his buddy while the other girl and I sat up front (she was driving). I was getting really miffed about being ignored, so I turned around to tell him off--and saw that he and his buddy were sorting through bags of coke in the backseat. So I thought "yeah...hell with this," noticed that we were coming up to the highway exit to a town where a friend of mine lived and figured it would be my last chance to get myself out of the situation, so I asked the driver to slow down by the exit, jumped out and made my way to a gas station pay phone (this was back in the day before cell phones), and called my friend's dad to come pick me up. And then wondered, in that oblivious teen-age way, why the dad was so panicked and screaming, "Are you OK? Did he hurt you? Do I need to get the police?" when he pulled up at the gas station. Looking back now, as a middle-aged adult, I completely understand how calling someone out of the blue to say, "Hi, Mr. Jones, it's Patty's friend Mouse. Ummm...my date turned out to be a drug dealer, so I jumped out of his car and now I'm stranded at this gas station right next to a biker bar. Do you think you could come get me?" would absolutely freak out poor Mr. Jones...but at the time, I was just thinking, "Well,
that was a crappy date." My point (and I do have one in here somewhere) is that young people do a lot of things without maybe thinking through all the possible consequences, and it's just sheer luck that most of us don't end up getting ourselves into worse trouble. I never stormed out of someone's car in the dead of winter...but you know, I
would have if I was drunk and/or upset. And I wouldn't have been wearing a proper winter coat and hat, because it would have ruined my cute date outfit and given me hat hair. (And my family and friends would have
sworn up-and-down that I would never do something so foolish, because I was a good student and a nice, responsible Catholic girl.) I'm lucky that I never got lost and froze to death, or slipped and fell into a river while walking home in a snit. But I can completely see how those situations can happen when you mix (possibly) alcohol and the bravado and inexperience of youth (especially with a male, since they don't have *BEWARE!* drilled into their heads the way girls do).
*I found out later that Mr. Bags o' Cocaine didn't even notice I was gone until they got to their destination about an hour later. Hmmph.