Regarding Jayme's ability to think about shoes, etc. --
My gut says she was planning an escape in her head for some time before she actually implemented it. She may have thought through many details, like making sure the red car was gone before leaving the house. It it easy to assume this was a spur of the moment run for freedom, but I would bank on her being more savvy than that.
Some people are more wired for details too. I recall the story of a woman who was abducted several years ago who was driven and taken various places blindfolded. She tried to memorize a few details along the way, thinking it would be valuable WHEN she was able to get away or get help. I don't recall any examples right now (I'll Google it after this post), except for the fact that they took her into a hotel (I think it was) and onto an elevator. By looking down under her blindfold, she could see the floors, so she memorized the type, color, etc. of the lobby floor and the pattern on the elevator floor. She was somehow able to get help and the floor descriptions were key in LE's ability to track down where she was. I remember thinking how smart that was - I do Finance work and am a stickler for details, but I don't think I would ever have thought to do what she did.
We all react differently to stress, fear, trauma, etc., but some people seem to have an inner strength or knack for keeping their wits about them better than others.