At an Independence Day parade in Highland Park, Illinois, earlier this year, 21-year-old Robert Crimo III opened fire on a crowd using an AR-15-style rifle, the Smith & Wesson M&P15, killing 7 people and injuring 48 others.

In the hours following, as police attempted to clear the scene, partners of Chicago-based plaintiffs firm Edelson, who were also attending the parade, hunkered down in a basement with their families, waiting for the green light to come out.