Then you'll want to use quick-firing precision guns like the Overseer's Guardian or Good Intentions. Instead, you'll want to either inhibit Sinjin using the Syringer Rifle or slow down time with a consumable such as the Jet or Buffjet. You could attempt to pacify Sinjin as well, but that would be a complete gamble with the odds stacked high against you.
After the first two are pacified, Avery should be a cinch. According to Cheng Teoh on YouTube, the trick is to wait a few seconds after pacifying the first, though that doesn't make it a guarantee. The raider to the right seems to be the most fickle target to pacify. Starting with the raider on the left, get them in your gun's sight and select the option to pacify.
This can be a difficult tactic to pull off, so if you take this route, be sure to make a save point before heading down the last elevator. You can skip negotiations and remain in the elevator instead to use the pacifying tactic if you have the Pacification Perk.