there is an error when two user migrate two different databases to the same target database concurrently

1.open two cmt in the same pc, select two different database respectively, then go to step 4, then let the two target table name be the same. then do migration concurrently(click the last "ok" at the almost same time)
2.I think, when one user is migrating a table to a target table which the other user is to migrate to, the same table should be locked, and only after the first user migrating the second user can migrate.