Hatfield, that is very much what rings true in my mind.
I run my theories by my husband from time to time. I described to him the type of helmet and JDW's history of hitting from behind. He confirmed that it was very likely and that it does not even take much strength to do a lot of damage, skull fractures easily from that kind of hit.
He told me about the type of helmets certain motorcycle clubs wear and they are chosen because they are excellent weapons.
I do believe she kicked him in the lower legs, esp having had defense training. And I believe she sprinted for the cornfield.
I also know that you can't travel thro grown corn without scratching your arms up....so they may both have those kinds of scratches/cuts. She may have scratched his arms too if he grabbed her in a chokehold of some sort. But she would be taught to go for his face if she could.
She was found bound. So I initially believed he killed her at the abduction site, but this gives me pause. But it could go either way. It is hard and unwieldy to handle a body. He might have bound her to make her easier to move out of the site and into truck or van. My husband pointed out that being bound by duct tape at the wrists would create a very good fulcrum for dragging her out of the field. (and into another later)
But she may have been knocked out and bound & gagged while he took the motorcycle back to get the truck to take and keep her, as it appears has been his mo.
Things went south for him with the prompt search & discovery.
Assuming the disposable underwear is because of no access to toilet facilities, my husband made a couple of other points. He said that it is also a torture tactic. It humiliates and de-personalizes the victim. The victim is helplessly humiliated (he likes that) and it helps him to objectify her.
I've no idea what his script for the barn hold time would be. But I am sure there is an aspect of him having power & control at all stages.
My husband and I both think he would have lost it and erupted into violence when she defied him, fighting him. Along with the practical reasons for regaining control of the situation.
Even tho it was a full moon, I do not think that light would penetrate to the ground through the corn. At that time he had a reasonable expectation that he would be able to return for the lost items at daylight.
I discussed the dynamics more in my last post, but I still believe them to be a powerful factor.
As a potential tip on his timing, it says that blood is found on clothing, but I wonder if there is dirt from digging a grave? same clothes or different ones?