Oh right, totally forgot that she glued his head back on and didn't dump the goo in the first place. Yea she is also incompetent. Good catch. A real hero would have bought it on that rock. Which is why the only good characters in the damn movie were the two shit out of luck pilots.
Also I don't think David was interested in the engineers at all. If she had returned to Earth he wouldn't have had time to learn about their ways. Still she is the cause of the entire problem. When she thought she wouldn't be able to leave the planet everything was ok but David did suggest that he could get her off of it... still I don't think it was much effort on his part to convince her.
The time line is confusing. It must have been more than a few month before Shaw went into hyper sleep but it is sold to us as being longer. Yet David said he had been stranded for 10 years or something. It's a mess.