In summary their whole ordeal was to ensure that the host doesn't die from otherwise fatal injuries. They wouldn't heal you however they wil ensure that you remain alive until help arrives.
However this wasn't their actual main aim. They were there to enhance the future mercenaries that would be working under him.
These people even after the explanation couldn't truly understand what was going on, he could tell in his current form. Accessing their minds was as easy as child's play.
Well most of them didn't understand what was happening so the plan was simply for Nous to inject them with he nanites which would enhance them not only physically but also mentally so that during their training, they could at least be taught.
After the first man, the others followed and each time, David had to descend to conduct the contract. He wasn't complaining about it though.
