Why is it important that Williams doesn't die in The Hunt For Red October?

For most readers, keeping Williams alive is important because he is one of the "good guys."  Williams and Ramius are both shot by Loginov, who is trying to destroy the Red October.  We want Williams to survive for the simple reason that we see no reason for him to die.  Williams is also important to the plot, and he needs to stay alive in order to help Jack Ryan and Ramius fake the destruction of the Red October, so that the United States can secretly bring it back to study. The reason that Williams is so important to Jack's mission is the fact that Jack Ryan doesn't speak Russian.  Williams does, and many of the crew and officers of the Red October do not speak any English.  Williams needs to stay alive so that Ryan has a way of communicating his needs with various crew members.  Williams is also a security blanket for Ryan.  Since Williams understands Russian, the Russian crew isn't able to say anything subversive that goes against what Ryan wants to happen. 

"Excuse me, Commander," Kamarov said. "Do you speak Russian?"
"Sorry, Lieutenant Williams here does, but I do not. A group of Russian-speaking officers was supposed to be here in my place, but their helicopter crashed at sea last night." Williams translated this. Four of the officers had no knowledge of English.