If you have three debates, why would you unload your clip on the first one? Throw a few jabs, enough to get her ticked and see what she throws back.
She unloaded on him last night and you could tell by her smug smiles. He got popped a couple times but that was her best and according to the "pols" it didn't resonate. Now he knows what she is going to do and can correct from there.
However, he still has PLENTY to hit her on in the next two debates.

at least that is how I see it.