It's not an opinion, it's a fact..you are going against known evidence with nothing to support it. it's like saying a round wheel won't roll. you want people to believe Cooper went down the stairs prior to the time he went down the stairs and was heard, and felt by the crew...same for the other hijackings..
can I say the flight went north, and not south, or Tina wasn't really on the plane?
they were aware of Cooper dealing with the stairs every time he attempted something. you assume way too much with solid evidence..it's pretty simple, they would know if he was on the stairs at 8:05...I'm sure all of this has reason for a suspect, it's the only reason someone would push against solid evidence, it has to fit somewhere, no?