An interesting look at the problem. But utterly wrong! Even if there are players from RU, they are not so much as to cause a collapse! Otherwise, by this logic, all international servers must crash every minute!
But do we know how close Mystel may have been to a limit on the resources it had before EU taking over TERA RU?
We did have the merge with Killian, so could have been very close to the limit without actually going over it.
We also have the NA players coming over in a series of waves as well.
As I see it, TERA RU players creating characters on Mystel might well have pushed it over an unforeseen limit on how much it could cope with.