((I hope I've understood the turn orders right, but VM me if I haven't. Magma Tomb charged on the turn that Jackson was about to attack with Dig (going second due to having a low speed stat to begin with, and the stacked penalty to speed from two Rock tombs), and would hit on the turn AFTER Dig hits. On that turn Jackson uses Protect, which is a priority move, so it should prevent Jackson being effected by Magma Tomb. I think.))
Well, nice to see you are good with pokemon, but you may have missed out on two factors, because of my first battle post.
Factor 1. Torkoal is the slowest final evolution fire type pokemon of all time. It is official. He is one of the slowest pokemon in the game, and I'd say they are equal in speed by now, Cauldero and Jackson.
This may have been overlooked for my first post, but I made him faster due to an element of surprise. Nothing more then just beginning the fight.
2. Besides that you made the attack first anyway. Imagine it this way: every time you attack is a new entire turn in an RP battle. In the games turns are one attack each, but RP battles tend to be one RPer's offense the others defense/response. If you use dig then I have to respond to that, and that is one turn. When Dig hits, and Torkoal hits that is turn two.
You are saying Protect would be used when the turn began a new correct? Besides all the things above Cauldero is going to use it as a retaliation style move meaning he hits as/after you hit. Think of revenge. Your pokemon ignores speed to go second on purpose.