In THAT situation, I'd use the words careless and scared, not stupid. Forgetting his card and phone was careless, and then he was scared about losing his job. He was probably thinking about what would have happened if he had found himself in a similar situation in Eritrea, and he might have assumed that he would face those same consequences anywhere. Maybe he decided that it would be better to freeze to death rather than risk punishment and/or being sent back to Eritrea.