There are many synonyms that can be used instead of "pulled the trigger." Some alternatives could include "fired a shot," "squeezed the trigger," "pulled the lever," "released the safety," "pulled the hammer," "activated the firing mechanism," "engaged the trigger," "discharged the weapon," or simply "shot." These synonyms can offer different nuances to the action, whether it is a quick and sudden movement or a deliberate and planned action. Ultimately, the choice of synonym depends on the context and desired tone of the writing or conversation.