Travel and TSA followup

I am back alive and well after flying to the West Coast and back. It was an interesting flight on the way there. After we found our seats on our flight out of Dallas, we watched an Asian man come down the aisle, clearly dealing with some mental or nervous issues...anytime he would have anyone come near him he would have big drama and throw his hands in the air and roll his eyes and then kind of hug himself...I watched him sit in an aisle seat with 2 women who were clearly disturbed by what they had seen also.  He immediately stuck fingers in both ears and rocked back and forth, which didn't help the situation any, making people wonder if there was going to soon be a loud noise on-board. Immediately after takeoff he jumped up out of his seat and crouched down with fingers in his ears and ran all the way up the aisle and all the way back to the back of the plane, by now, everyone was watching this guy as he ducked into the restroom on his way back up the aisle. I must admit, by now, I'm saying silent prayers, and I shook my already sleeping husband awake, not knowing what would happen next. One of the ladies called the flight attendant and told him that the man carried a lighter into the restroom with him. At this point the attendant went back to the back and banged on the door and asked him if he had a lighter, of course the answer was no, so the attendant opened the door and removed the lighter.  The man eventually came out of the restroom in the same position that he entered in, fingers in ears, and took his seat where he rocked for the remainder of the trip, while under the watchful eyes of every other passenger on that plane. I understand that there are a lot of people with mental issues, and this may be the case, but, my first question is, if all passengers have to pass through the scanner, how would this man get through with the lighter? I truly believe that all the drama that goes on in the lines with having to take all jewelry, belts, and shoes off and opening your laptop to put through the scanner is for no other reason that to cover their backsides when someone does take out another plane load of people.