Paddock definitely was not a pro. A pro would have baited Campos in and shot him dead inside his room and then kept on doing his work.
Shooting through the door makes no sense at all to me. This is ridiculous. Way to alert everyone around. It does not add up.
Saw it somewhere on the Internet, not sure this is true, that Paddock had been checked into multiple hotels in Las Vegas simultaneously. This is a method used by Las Vegas con men to try to avoid people who are following them and people they owe money.