Casket speculation

Well supposing the Jockeys[url=http://www.youtube.com/watch?v=i1vH2rjUshk]this[/url], seemingly innocent and waiting for a million year or so of evolution and then, "Hello my baby...". April fools! Seriously now. "I think that they could be where the Engineers fill their ampules. Insert an organism into the casket and the dna gets rewritten into a parasitic organism/virus that is useful to the Engineers be it a weaponized xenomorph or a biomechanical space suit or even ship components. The engineers gave us directions because they knew that by the time we got advanced enough to find them, we would have enough population to provide tons of raw materials." Why not there's nothing to contradict the idea although it would be more likely that humans would be used as a means to make more and more space jockeys, not unlike [url=http://en.wikipedia.org/wiki/Threshold_%28TV_series%29]Threshold.[/url]

At first, I thought the ampules just made more Jockeys, but now Im not sure. What holloway beomes seems different from whar fifield becomes. If the ampules do make more jockeys then maybe the caskets are how they store themselves for future invasions