I think the problem is that he's used to having his strong body which was trained through boxing and heavy labor. He tends to forget that he has a softer weaker body with hardly any muscles or stamina. It also works against him that he's accustomed to depending on only himself and is uncomfortable with and forgets he that he has people he can rely on now.
True true, you actually might've hit the nail on the spot with that one :3 I completley agree with that
For short..He lacks common sense.
Don't get me wrong.Being strong is totally necessary but you need instinct and common sense more for survival.
I might be wrong, I dunno, but knowing what kinda guy guy Taemin is, and how he was "brought up" is it really hard to imagine him not make such foolish decisions like following strange guys and turning off his phone? I mean, I'm sure he has some sort of common sense and all, but I'm not even sure if he was taught about safety and the do's and don'ts of modern life. Love him to death, but he's still a hard-headed smartass (and an entertaining one at that:3) IT's not hard for me to believe that he'd make these mistakes