Here's a hot take straight out of the oven boys: there's a strong possibility that he won't because he's Donald Trump. When Donald Trump crashes, he crashes hard. He's going to make a fool out of himself over the next week. There isn't going to be any "damage control". He's going to foam at the mouth all over the place; at CNN, at ABC, at MSNBC etc. He's going to look very unhinged when he does this. The most salient takeaway of the debate is that "Trump cannot be trusted with nuclear weapons" and he's going to solidify this takeaway and dig a hole for himself. If he gets unhinged enough, he might bail out of the debates.
Stop treating Donald Trump like he's a normal candidate. He's not. He's mentally ill and needs to be put in a straightjacket for his own safety and well-being.
Maybe true, but you're forgetting about his ego. He's not going to let it look like he's scared of getting his butt kicked by a girl.