Once upon a time, the wardrobe of the horror genre consisted of diaphanous white gowns and black vampire capes.
These American soldiers carried flame throwers and guns, and saw the innocent families and denizens of the town as something akin to expendable cattle. Therefore, the protective suits – on one hand a protection from danger – also became a barrier to communication, an impediment to human and humane behavior on the part of those who wore them. Behind those suit masks, we couldn’t see how the soldiers felt, or if they were agonizing over their difficult choices. We could only see how (horribly) they acted in the face of fear.
Some films, such as Outbreak (1995) play with the conventions of the hazmat suit by featuring scenes wherein the protective suits rip and tear, and our heroes are exposed to a bug and therefore mortally endangered. At another moment in the film, a scientist (Dustin Hoffman) is so convinced that he has discovered the cure for hemorrhagic fever that he (foolishly, in my opinion...) removes his helmet in the presence of the infected. Fortunately for him, his gamble pays off.