Woah. You just rocked my world. Of course! It makes so much sense now.

So as soon as word got back to Ben and the Others that Mikhail had his brains liquified by those sonic gate-things, they went back in time to find an earlier Mikhail pre-liquified-brains-death to bring back to the present. Genius!

And if the "incident" in the Swan station was time travel related (I'm thinking the same person/bunny from different times appeared there at the same time and tore a temporary hole in the universe...or something) well...that would explain why Desmond was able to travel back to England and Penny in a time before he arrived on the island when he was late entering the numbers.