Mid mast, or even mast-high swell would be manageable. Big breakers would be bad. Swell, I'm sailing. Big breakers, I don't know; especially when you add the issue of a bad motor. It also depends on how big. Pitch pole big?
I think the rudders wouldn't hold up to big surfing, possibly the dagger either. Your plan, (assuming the tie-point holds), would have breakers coming over the nose, and dropping on the deck. Not sure how much I trust the deck, but certainly not that much. However, if the motor is stalled and I get into larger than 15-20 ft breaking seas, a sea anchor might be my tool of choice. But, I'd likely strap in and stay in the cockpit.
Contrary to your statement, I don't think Roger was being terribly irresponsible in showing the boat could run in high winds and a big swell. That was one of the selling points to me. He said something to the effect of, "we don't recommend sailing in this type of weather, but it's good to know the boat will do it". I looked at those conditions as way worse than I would ever intentionally experience - indicating that the boat would be adequate for my planned use. It was a given that those guys knew the local waters and had some experience in those conditions.
Also, the skipper is a huge part of this equation. A good skipper that knows the waters and regularly sails the conditions would probably not bat an eye. BOAT has probably sailed in conditions almost as bad as Roger's video, if not worse. I'm sure several others have also - concerning big swell and high wind.
But, I'm sensing your question is more about what if it's really worse than that. Maybe "Perfect Storm" like conditions that would sink a 100+ ft seagoing vessel that was designed to be out there. If so, your strategy might have some minimal value, but your best bet would be Prayer and hope that your guardian angel wasn't on a smoke or coffee break.
Having several tons of water drop on the deck would be a real challenge for our boats. I won't be below taking a nap when it happens. 
More importantly, there are fair weather conditions that can wreck you. Watch a video of haulover inlet for example. Know the waters you're in. Know the forecast. Take the precautions you discuss. Then, enjoy the experience. Keep your Bluewater trips to manageable distances between safe harbors.
Just my opinion. Take it with a box of salt.
