What Happened to the Engineers on LV_223?

In Prometheus Fifield and Milburn stumble upon a pile of dead Engineers in their Bio-Suits in the East wing of the Alien Temple. Some of the Engineers show busted heads, others show busted rub cages. What could have caused this? [center][url=http://www.prometheus-movie.com/gallery/view/img/121][img]http://www.prometheus-movie.com/media/prometheus_screencap30.jpg[/img][/url][/center] Obviously, something got "out" in the Temple and prevented the Engineers from departing from LV_223 some 2000 years prior to the events of December, 2093. When David activated the holographic recording of the Engineers running away from something, the crew follow them to entrance of the Ampule Room where one of the Engineers perished at the foot of the door before being decapitated by it. [center][url=http://www.prometheus-movie.com/gallery/view/img/119][img]http://www.prometheus-movie.com/media/prometheus_screencap28.jpg[/img][/url][/center] Why were the Engineers seeking refuge in the Ampule in the first place? Where did they go? Were they eventually found in that room and dragged to where Fifield and Milburn discover their dead remains? Also, where are the beings responsible for this? Did they disappear? Or perhaps did they hijack one of the other Juggernaut Space Vessels as it was attempting to escape and this is what brings us to ALIEN? Could the original Xenomorph creation (Seen in the Mural) be the cause of this massacre? Could they have gotten on one of the ships without the Engineer knowing? Or was this something else? Could it have been a different breed of Alien? An interesting thing to note is that the way in which the Engineers were all gathered in one place and then killed (I'm assuming) mimics that of what we see in ALIENS and even a deleted scene of ALIEN - where the Xenomorphs drag their victims to a spot, near the Hive's core where they can be impregnated and the offspring born without danger. Could an Alien Hive have been created on LV_223 inside the Engineer Temple? Could a premature Queen have emerged and started reproducing and forming a Hive? If so, then what caused them to disappear? Why did Fifield and Milburn not discover Hive resin on the walls? Or any remains from the antagonists? Could the Aliens have ventured to another Temple in search of more hosts? Or did the Engineers find a way to stop them somehow? This topic contains many, many, many questions for you all to dissect and speculate over. Post your thoughts and opinions on this here! Hopefully we will get our answer when Prometheus 2 surfaces!