that is what Historian John Keegan called "the Mask of Command.
I have seen faces like those... and usually those faces come with life and death situations.
The people who you saw in that photo, ranging from the Secretary of Defense, to the SOS, to the President, to Admiral Mullen... were watching people carry out their orders. Especially for POTUS (signed the execute order), the Chairman of the Join Chiefs, chain of command with JSOC, and the SECDEF, again direct chain of command.
Now I can speculate what they were seeing... I won't. Suffice it to say, they were watching the results of those orders. Realize that until relatively recently, in the modern world (Generals did watch from hills all the way to WW I)... this was not possible.
This is what a Junior Officer was supposed to experience, not a Head of State, or the overall commander of the Armed Forces.
But yes, when Rachel asked, have you seen those faces? Yes, yes I have... why I was able to put my finger on it. Mask of Command... if you can, read that book.
http://www.amazon.com/Mask-Command-John-Keegan/dp/0140114068I rarely recommend books from Military Historians, but that one... if you have never served where you will see that face, and are truly curious.. that is a good book.