If there is no communication whatsoever between Russia and the rest of the world (highly unlikely), then the network will fork. The main chain the rest of the world follows will lose the Russian hashrate, resulting in longer block times for a maximum of two weeks until the next difficulty retarget.
not really the case, it just means any russians making blocks are not seen meaning that other nations mining pools get to submit their block result meaning more rewards for the other nations to share with one less competitor nation
three is no actual direct correlation of hashrate vs time per block
imagine it this way
if there are 10 olympic runners each averaging a time of 9.5-10.5 seconds in a 100metre run.. only 1 can win
take one person off the track does not make the other runners slower. it just means the chances of the 9 remaining runners winning increases. the average win is still the same average. but now 9 people get more wins when they run regularly
what does cause a speed up or slowdown. is if each of the runners are using more or less muscle(asics) then previous fortnight. meaning the average time over a fortnight has changed to be more or less then the needed average.
taking one competitor out of the race does not impact the speed of the other runners