Things start with a number of Reinforced Surveyors and a Badass Surveyor coming in on you. In addition to that, you have a number of Hyperion Assassins coming at you from the West. Take out the Surveyors first as you cannot get critical hits on them and they can pepper you with shots. After that start working on the Assassins. There are at least 2 rounds of Assassins you need to deal with.