get the drop on

verb2

1. •
   (informal) To point one's firearm at another person, thereby gaining dominance in a situation.

   • He got the drop on them and proceeded to shoot and kill them before they could fire a shot or respond.
2. •
   (informal) To obtain an advantage over another person, by acting before that person.

   • We’re always getting the drop on our competitors because the owner really knows the business and can act fast.