[Trailerpark Badass]

It was a military area where the sound of helicopters would not have been out of place. Somebody at this location would not be alerted by helicopter noises.

The Tweeter noticed it, and even said something to the effect of a helicopter being a rare occurence.

[gusty]

Abbotobad was the home to a Pakistani Army division and its national military academy, described as their version of Sandhurst. I would tend to believe that helicopter flights were common in this area. The same tweeter also said that he thought it was a Pakistani training mission in progress, thus contradicting himself.

[RummyChick]

There were two people tweeting about it. If they heard it,Osama heard it.

I am more likely to believe a shoot out scenario than one where they quietly snuck in and found him in a bedroom and OSama never knew they were coming.