Creation Revisited part 2

Thanks to BigDave I have thought of an interesting twist in the plot: We are talking an all Engineers based plot. Ok, probably Engineers are benevolent creatures. Not Gods. But have found a key to eternal preservation or their race, a mix with an alien indigenous DNA they have discovered at some time in their journeys through space. They have visited Earth and possibly other Earth-like planets. They did not give birth to human race or other human like races in the Cosmos. But they are so good, they want to in a way intervene to the evolution of man, by manipulating our DNA, making as different from the rest of creation, able to become an intelligent life form, to the point we can understand the pictograms and visit the resting place of our forefathers to be gifted the secret of eternal life, for which by the time we would be entitled. That would be our price. Now comes the nasty part. I refered to as resting place, cause their race was dying. They would become extinct as space jokeys, but would continue to live through their DNA gift to their children. Perhaps they lived as immortals enough, just to realize that immortality isn't everything after all, and moved to the next evolutionary stage of meeting their afterlife destiny. Still as the chase for immortality would logically be a primary goad of their human off springs,they wanted to allow man to get this secret too, live with this for as long as they would like, and then, like the sjs, they would freely decide to meet themselves their own afterlife destiny. Here is "A King has his reign, and then he dies, it's inevitable"...probably the ultimate driving thought of the sjs. Alas, some Space Jockeys, probably addicted to the power of the artificial immortality, wouldn't like to stop existing in this life, so they plotted and killed the other sjs who probably didn't resist at all, and just kept watching them with compassion. As long as the benevolent sjs had the control of the xeno life form all were good. From the moment the bad guys took charge, they also lost control of xenos. These xenos in the end eradicated them too. Probably, the LV-426 ship was the last of the good sjs, where they tried to resort, but the bad guys releasing the xenos killed them all. The ship on LV-223 was the other last stand of the good sjs, but soon got wiped out by xenos, probably passing from the ship on LV-426 through the portal depicted in the trailer. So we end up with the only solution the bad blue guys could use to secure the immortality of their race. They would somehow save their race in the urns as DNA life mixed with the xeno DNA, and would wait , just wait for the first humans to arrive to come in contact with this DNA and give rebirth to a bad blue guy who would alone be enough the set the derelict on course to Earth for the obvious reason. And all that, because these bad guys, want to have their physical form as Engineers, in order to enjoy their immortality and as so, they have no second thoughts about eradicating all humans on Earth. And since the first victim is on minute 28 of the movie, It appears that all nasty creatures, are already there, loose, before any crew member became truly infected by a xeno-blue guy DNA. And all that because of the general mess that had wiped out the blue guys. Ok..mind boggling again. Thanks for putting up with this.