By vigorously do you mean for a short period at high heat? If the meat is in a liquid,it shouldn't reach over 212 degreees no matter how high the burner temp. Also, by cooking them in the marinate I thought I might be in a sense boiling them and drawing out the moisture from the meat cubes by the ingredients of the marinate. Not so? I usually marinate the meat for 3 days before cooking and usually add a teaspoon of lime juice (I think this adds a better flavor than vinegar) so the meat is quite tender before I start the cooking process, Also, in your offerings on my caveman dinner post the list include 2 tumble weed rub; is that 2 tablespoons? I tip my hat to you for all the good insights you provide.