The nightmare that mediators have long dreaded has come true: a mediation party pulled out a gun this week and shot the other party at the close of a mediation. The parties had a contract dispute, and the plaintiff, a man named Arthur Harmon, had sued the defendant, Steven Singer, for $17,000. The mediation took place at the court-appointed mediator’s law firm in Phoenix; the plaintiff was not represented, but the defendant was. At some point the plaintiff reportedly said he needed to go get something from his car; after a prolonged wait, the others assumed he was not coming back. The defendant and his attorney, Mark Hummels, headed downstairs and were in the lobby when the plaintiff appeared and shot them both. The defendant was killed instantly, his attorney died later, and another bystander was injured. The shooter escaped in his car, and subsequently was found several miles away, dead in his car of a gunshot wound.

Mediations are stressful. The parties are by definition in high conflict—if not, they wouldn’t need a mediator’s help to resolve their dispute. Mediators have many techniques to reduce tension, but most of us have stories of a party who was overwhelmed by the stress, such that the mediation could not continue. In America, people who feel stressed often turn to guns, so mediators have long worried about how to prevent a party from bringing in—or using—a weapon in mediation.

One option is to screen parties ahead of time for the presence of domestic violence. This is standard protocol for divorce and domestic relations cases, but virtually unheard of in a business case. Michigan’s new Mediator Standards of Conduct recommend that efforts be made “throughout the mediation process to screen for the presence of an impediment that would make mediation physically…unsafe for any participant.” (Standard VI.A.) In other words, the mediator should be on alert for any hint that a party is getting angry enough to physically harm the other party—or the mediator. However, in this case, the angry party left—which is an acceptable option for someone who can’t restrain their emotions. Whether the mediator could have detected that this party was angry enough to return and shoot the other party is hard to imagine.

Another option is to hold the mediation in a facility with a metal detector, e.g., a courthouse. This is standard practice in Michigan when mediating cases where one party has taken out a personal protection order against the other party. One of my colleagues has mediated two family probate cases recently where she learned about gun concerns during pre-mediation conversations with the parties, and as a result opted to hold the mediations in local courthouses.

It’s impractical to hold all mediations in courthouses, so which ones are “safe enough” to hold in an attorney’s office? The Phoenix case was a simple business case and didn’t involve a large sum of money. According to court records, the defendant had hired the plaintiff to refurbish and move office furniture at the defendant’s business, but not all of the work was completed, so the defendant paid only $30,000 of the $47,000 contract, and the plaintiff sued for the balance. There is no indication that the parties had any relationship other than this contractual one. If there was ever a case that would not require pre-mediation violence screening, or extra security precautions, this was it.

We also don’t want to err on the other side, and call the police or end the mediation every time a mediation party expresses outrage. So, in the end, we cannot prevent tragedies like this. We can be more vigilant, and more aware of our options, but what this story reminds me is that the best thing I can do as a mediator is pray.