A couple of discrepancies

How did the saboteur aboard the sub (presumably Vaslov) know that they'd have to fire a torpedo to break through the ice? They might've gone the whole trip without having to use the torpedo. Why did Vaslov go down to the torpedo tubes to watch it happen, but then help out when disaster struck?

At Ice Station Zebra, the Soviets had a man, as did the British. According to the dialogue, there was a shoot out in the snow and only the Soviet agent survived, with the Brit being left "out there" in the snow. And yet, when Jones and Vaslov survey the dead in one of the huts, both agents' bodies are accounted for. How did the British agent's corpse make it inside?