Evolution turned against SJ

Taken the last trailer and the interviews given by Ridley Scott I believe that something went wrong when the engineers tried to start evolution on a planet. One of their leaders got infected on this planet and brought back the infected biomass to the home planet Zeus. By the time he deceased the mutation took a life on it's own and started to infect anything on the home planet which was alive. There are quotes in the film that the ceiling is changing. I believe this is the life form which got out of control and looks for an organism to have a shell and further develop. This also connects to the biomass in the container David is opening which in the very first trailer looks green and in later trailers looks black and probably seems to go into the space suit of one of the crew members. The organism recognizes that David is a robot. Potentially one of the crew members could be mutated to an engineer having the capability to fly the derelict space ship. I don't think there are a great many engineers on the planet Prometheus is landing. I believe none. If there were they certainly would be more powerful than the Prometheus crew and there wouldn't be a need to hide from the Prometheus crew.