If you put a bullet in the shoulder/lungs of a bear, it will die...eventually or perhaps immediately. Put a bullet in the guts and he might die a painful death if he is lucky. I don't understand you guys who say the guide better not shoot; I suspect most of you have not hunted much dangerous game. My last brown bear was shot with a .338 Win Mag and 250 AFs. Bear went down when I shot - dropped like his legs were pulled from under him. Guide followed up with a shot, and I put in a second one as well. Bear went nowhere.
My advice: if you have a problem with a guide shooting your bear, don't book the hunt. Your attitude alone will sour the hunt. You are essentially saying you killing that bear single-handedly is more important than human life or at the very least, your ego is more important than an animal suffering longer. I sure would not want to be your guide.