Law's probably not going to die. I don't think it makes much sense for it to happen when Luffy isn't around and if Oda doesn't even have the balls to kill kinemon, I have absolutely zero faith that he would kill Law. Law's awakening will probably seriously injure big mom, but take him out of the fight. With Marco and Chopper around, I doubt it would kill him tho.
Also, was it confirmed that Kid's awakening is also a last resort technique? Because Im feeling like that was only true for Law's, as we already know that Law's fruit has a big drawback, whereas Kid's was never said to have such a drawback. Kid's awakening also just isn't as overpowered.