My thoughts are in blue, words to delete are in red, suggested rephrasing is in orange.

The panicked herd trips over itself, clawing and shoving and running into the backs of those in front. The fallen receive two bullets at close range because Malcolm is going for fatalities, not injuries. Blood splatters his face and lips as he shoots an old man in a Rascal—there are many old men riding Rascals—in the side of the neck from three feet away. The bullet leaves a hole wide enough to see through. Malcolm reloads on the run. The herd needs further culling. I definitely would not start this way. It's dumping the reader directly into the fiction, and that is not the purpose of a query. A query introduces the piece of fiction in the role of a third party, not the fiction itself. Also, I was just thinking it was cows until the third line, so confusion is rampant, and the reader is being thrown directly into gun violence, so there's nothing about this approach that is working, imo.

Malcolm Sitwell is a grandfather leading a quiet existence, intent on avoiding conflict and anything emotionally difficult. Even though he’s just 50 and still works, some would say that he is already retired. Anyone would seek a quiet life if they witnessed their wife’s face getting crushed by the wheel of an F-150. I feel like the hook is lost here - it's at the end of the para. I don't understand his reason for seeking this life until I get to the end, and we've got this emotional swerve, from a quiet life to someone's face getting crushed under a tire. Also - with no setup for that tire crush, I was immediately thinking this was a farming accident, and that Malcolm was responsible for her death. There are a lot of details here that the reader isn't getting, and because you already know them, are assumed on your part. Your brain is autofilling information - like the fact that she died b/c of traffic violence / domestic terrorism, or that it's people being shot in the opening para, not cows - that just isn't in the text itself.

In the trauma of his wife’s death, Malcolm latches onto his daughter (April) and two granddaughters (Mackenzie and Lizzy) in a death grip. But when Mackenzie and Lizzy are killed in a school shooting, and April commits suicide months later, Malcolm’s grief transforms into uncontrollable rage. The annual NRA convention just happens to be in Malcolm’s hometown. Armed with nothing to lose not sure if this phrasing works, Malcolm plans on attending.

The Safest Square Mile (88,000 words) is a psychological revenge thriller that takes aim at traffic violence, gun violence, generational trauma, and grief. Comps include The Revenge List by Hannah Mary McKinnon and I Kill Killers by S.T. Ashman.

I have a BA in journalism from the University of Oregon and I work as a legal content writer. I am also a professional athlete and have blogged about my sports career since 2008. My most popular post has 100,000 individual views. I have a strong online presence and marketing background.

So you've put yourself in a tough spot - critiquing a violent culture while asking the reader to have a sympathetic view of a mass shooter. That in itself is going to narrow down both your reading audiecne, and people willing to represent you. I'm sure you already know that, just putting it out there.

In terms of the query, most of my thoughts are above, but overall we need more plot. All this does is tell us what Malcolm is going to do and why he's going to do it. But... what's the point? What's the plot? What does the main character want? What obstacles stand in the way? How will he overcome them? Right now all of the tension just feels pyschological which is fine - and how you've identified it yourself. But again, if you're asking the reader to have sympathy for a domestic terrorist - no matter who they are shooting at - you're going to need to have plot as well, and it will need to be present in the query.