I think he does have the discipline to step back, a guy who unable to hold his tongue and keep his cool, does not have buildings bearing his name all over the world.
I am just repeating my post that is above to you: It could be Trump wins either way by being attacked or holding back and being calm - if attacked the audience sees a pile up - one guy against the big bad world. A master strategist goes into a fight where there are multiple ways of winning.
The ankle bitters on stage have only one way to win. Hell, maybe even winning is not the point for them now that their master has ordered them to kamikaze themselves to stop Trump. They lose by attacking Trump. Attacking Trump means he is in front. They seem desperate. My amateur take on it.