Like many U.S. workers lately, Maricarmen Molina has mentally mapped out how she hopes to escape should a gunman ever enter her workplace.

The 26-year-old shop steward at a New Jersey apparel warehouse said she plans to sprint to the back of the sprawling building and hide between racks of nearly floor-length dresses, trying not to make a sound.

It is a strategy she re-evaluated over the weekend as back-to-back mass shootings unfolded at a Walmart in El Paso, Texas, and outside a bar in Dayton, Ohio. After so many such incidents, Ms. Molina said a shooting attack no longer feels like a fluke event that could happen to someone else. A few months ago, she went so far as to test her plan, hiding in the dresses as a colleague confirmed she couldn’t be seen.

“Sadly,” Ms. Molina said, “we live in a world where you should always suspect the worst.”

Many workers and managers say talking through similar what-if scenarios has become water-cooler conversation this week, especially in stores and other places easily accessible to consumer traffic. Even before the weekend shootings that left 31 people dead and injured dozens, some say they plotted escape paths or hiding spots. Others stocked insect spray on desks to disorient a gunman or purchased doorbells to use as makeshift panic buttons.