My double agent theory.
There is no way that Coulson wouldn't have been consulted before killing Pullman. He would also never have gone ahead with that.
It appears the guards were shot in the head, but I think with that gun Fitz and Simmons made, the one that makes people pass out. Same with the lady in charge, who was also in on it.
Grant is now a double agent trying to infiltrate Hydra, via Pullman.
Start of next episode they will make their escape from the plane and we will then see the dead people being revived.
I initially thought that too, but then saw the damage the gun did to that guys head, unless that was an cgi effect continuity error.