I thought it was a good reaction, personally. Was he supposed to leap up, knock over a chair and run out of the room screaming?
He finished what he was doing, gave time for more information to come in, and mentally prepared himself for what was outside of the classroom. Seems good to me.
When will republicans explain to the American people that democrats are a low life cut throat rotten party, who will make trouble over anything decent people do even in the midst of a national crisis? The real issue, as always, is the filthy left wing response.