If a 30k user votes to close a question, and another 30k user has already voted to close the question, then the question immediately gets closed.
If a 30k user votes to reopen a question, and another 30k user has already voted to reopen the question, then the question immediately gets reopened.
This will be the policy for all questions that have a score of 0 or less, except those questions that have already had at least 1 close history and at least 1 reopen history.