This event is significantly more fucked up than it's normally portrayed: Pola had been crippled by an air attack before the surface battle and was unable to act as her two sisters Zara and Fiume were sunk by Warspite and the British force before her crew was taken off and the seaworthy but powerless Pola was sunk.

So if you ever wonder why Pola drinks, its cause she watched her sisters die while completely unable to do anything.