After solving Primm's quest, I noticed when I was heading back north to drop of a few supplies, McGee had died. Therefore I loaded a previous save and watched tweedle dumb and tweedle dumber heading off into the dessert to serve as gecko food. I managed to protect McGee but I lost track of the lieutenant. I must say: I'm intrigued by this behavior, is this some kind of odd glitch? If not where are they heading? Following and protecting them was not exactly in my schedule.