All sUAS must give way to ANY manned aircraft regardless of "who was there first". If a manned aircraft enters in an area where you're flying you should land immediately with no hesitation. Anything else is reckless and very bad judgement.
But what if you're in a position where you can't land - i.e. over water? Recall the story about the two guys who were arrested in NY after they were taking video of the George Washington Bridge. While they were filming, an NYPD chopper noticed the Phantom and began to approach, following it as the Phantom pilot made a b-line to land at their location. When they landed, they were swarmed, and charged with felony reckless endangerment. The charges were later dropped when the cops couldn't prove the drone actually came at them. Point is, there are always two sides to any story.