That will never happen.  Since the re-write, only he can create blocks as the client was updated to require blocks to be signed by him, making only his blocks valid.  According to https://www.bittrex.com/Status, it has been over a day since any new blocks have been generated.
No one else can generate block, hence no one else can process transactions.  Deposits to Bittrex, withdrawals... even sending MID from one person to another is impossible now.

Horray for centralized block chain control.