Nice to see all you 'professionals' want to hang the guy. Maybe he really was 'lost' on board. The toilet and cockpit door are very close....give us a break.
The guy must of been acting pretty unreasonably. Any reasonable person after knocking a few times, or waiting a reasonable amount of time would ask the cabin crew for assistance, as the person in the "toilet" might have a problem. Also, it's a very large aircraft with plenty of toilets on board, if he needed it that badly he could of found another.
Instead of this, it would seem that he banged persistently on the cockpit door, and ultimately needed to be restrained as he was deemed a security risk.
Whether drunk or not, people should be able to fly on an aircraft without causing a nuisance.