When your neighbor sets fire to his kitchen, you do not hold a conference with your roommates; you put out the fire and administer first aid.
Wikipedia's structures are designed to build a collaborative encyclopedia, not to deal with actual emergencies. When an actual emergency may be in progress, notify the proper authorities and take appropriate measures to limit the damage. A quiet, calm, and firm approach is generally best. If you can deal with the problem yourself in a quick manner, then do it promptly.
Be sure to report the results and explain the story behind the scene, but it is of utmost importance that the problem be dealt with first.