He succeeds, but only because Walter didn't expect him to actually go through with it. He intercepts the hand way too late, and all it really accomplishes is smearing the ketchup Rudolph splotch to his cheek. He seems shocked for a few seconds but it quickly fades as he squeezes Danny's hand.

"Oh. You are going to regret that."

His slider has been abandoned. He points the packet at Danny and gives it a squeeze. It becomes immediately apparent that that was the wrong way to go about this condiment war. It explodes, sending mustard flying in all directions.