That may work, although I never could do it, nor could my dad, who hunted abs for 60 years. Moreover, I don't believe that there is a "spot where all the muscles meet" -- I'm pretty sure, based on having processed a few hundred of the things, that abalone have only one muscle, the foot muscle; one end attaches the animal to its shell and the other is used to attach the animal to a rock.
In any case, in my experience (and my dad's), whacking the muscle once it was removed from the shell and the guts had been trimmed away never caused it to relax very much, certainly not enough for eating. Rather, we sliced it and then pounded the slices to tenderize them, as you would a boneless chicken breast. Done properly, the meat is fork tender when cooked.
This is an interesting site with a lot of information about abalones, including some good photos:
Abalone: Introduction