I've only seen RINOs trying to burn the GOP down when they don't get the nomination. I haven't seen Trump do that.
The real question is whether Trump himself would support the nominee if it isn't him, or if he would instead encourage his supporters to stay home or just write him in. At this point, most of his supporters here seem - at least to me - to say that they won't support anyone who challenges hom at wins the nomination. That's the real "burn it down" question.