The mental exercise almost always starts the same way for me: with a tweet. For other people, it might be an email or a TV bulletin or a Snap. Whatever the medium, it’s a report that there’s an active shooter somewhere: at a school, government building, office, sporting event, concert, or a theater.

Nearly six years ago, after the massacre in Aurora, Colorado, Garance Franke-Ruta wrote in The Atlantic about the ever-so-predictable aftermath in the days, weeks, and months after a mass shooting. After the Parkland shooting, The Boston Globe laid out a similar sequence. But these are about how society and the nation grapple with what happens afterwards. There’s another process at play, too, which is the personal, individual sequence of ever-shrinking hopes for a good outcome whenever there’s a new report of a shooting.

The first step, of course, is hoping that it’s a false alarm. Frequently, though not frequently enough, it is. Someone will have reported an active shooter, but when police arrive and clear the scene, there’s no one with a gun and no one injured. Or perhaps a bystander thought he or she heard a gunshot, but actually only heard a car backfiring. We can breathe a sigh of relief and get back to life as usual.

But far too often, it’s not a false alarm. The pit in the stomach gets a little more real. Perhaps, one thinks, it will be a suicide—terrible for the victim and all of his loved ones, but at least no one else was injured.

Sometimes it is a suicide. But far too often, it’s not, and the pit in the stomach gets a little bigger and sinks a little deeper. Then perhaps it’s an interpersonal dispute. The shooter is a disgruntled ex-employee seeking out a boss, or a jilted lover. That doesn’t in any way diminish the horror of the shooting—just take the death of a 16-year-old murdered by an ex-boyfriend at their school in Maryland last month. But at least it means the scale of the violence is likely to be limited, and the fact that an act of violence isn’t random may offer some minor reassurance.

Sometimes that’s all it is. Early reports about a shooting at a YouTube complex in San Bruno, California, on Tuesday, suggested such a dispute. Far too often, it’s not that, though—it’s someone opening fire more or less indiscriminately. The pit in the stomach gets still larger and deeper. One hopes that in that case at least the toll will be low: The shooter will have injured, rather than killed, his or her victims. Or if there were deaths, perhaps there were only one or two, as in most shootings, and not six, or eight, or 13, or the 17 killed at Parkland.

Once a shooting has entered that territory, there is little left to hope for. Some find themselves wishing that a shooter was motivated by insanity or rage, not by support for some divisive social cause or agenda of hate. Muslim Americans have spoken about the sense, whenever violence breaks out, of hoping that whatever happened, the perpetrator isn’t a Muslim. When a gunman opened fire on Republicans members of Congress practicing for the Congressional Baseball Game, there were instantly hopes that, amid an already tense political environment, the shooter would not be politically motivated. As it turned out, however, the perpetrator had strong anti-Republican views. Yet while it can sometimes be a blessing when there’s no divisive social cause motivating violence, the reverse can also be true. As if the scale of the carnage in the Las Vegas shooting were not bad enough, the continuing mystery of what motivated the gunman makes it seem even more terrifying and random.

It is a brutal, mentally exhausting and painful process to go through this checklist—nothing compared to the trial of being caught in a shooting, but a kind of slow-moving social trauma, one that every member of American society experiences individually but at the same time, dozens of times a year.