During the mission in Vorkuta, Mason understands Reznov and his allies in clear, albeit accented English, but the prison guards and other enemies are in untranslated Russian. It could be a case of Just a Stupid Accent... or it could be a mild form of Self-Serving Memory on Mason's part. Given his friendship with Reznov, it's likely in that memory, he tuned out whatever the guards were saying so he can focus better on his allies' chatter instead.
Reznov failed his escape from the gulag where Mason managed to get out, and the story outright admits that he then died after his re-capture. Either he was shot on sight for invoking such a brutal uprising, or being a cruel Russian imprisonment, they took an already weary and aching man and made him die slowly but miserably. The embers of the comrades from the Soviet trenches were all washed out but what Reznov left within Mason to carry on his vengeance and legacy, and all by cruel, opportunistic bastards that fundamentally undermined everything Dimitri and Reznov fought for, effectively ousting one dictator in the Nazis for a new set in their own people.
In "Executive Order," after saving Weaver from his imminent execution, he has a patch taped over his left eye socket. Why would Kravchenko and his men bandage his eye after putting it out if they were planning to execute him anyway?
Maybe it was Weaver himself.. Or Kravchenko did it as some sort of twisted mercy. So they can keep him alive to futher torture him.
