You may be right. I went back and looked at it frame by frame.
What I did notice is that he brings something in his right hand. He used his left hand to pull object from coat pocket.
Don't you need a stylus to operate a PDA? Rather than reach into the pocket twice and be detected, maybe he brought in the stylus in his right hand.
A final thought. Maybe the furious writing with the right hand was a diversion to draw attention away from the left hand operating a PDA.
All pure conjecture of course.
Maybe he thought Bush might wet himself if Bush got too close or something. "Depends" briefs maybe?