FAQ

It's possible he did have one and removed it before the assault on the main force in the village. Alternatively perhaps Doc wasn't equipped with silencers for his weapons because he needed to make space for medical supplies.

The film tiptoes around this idea. Red asks Waters "Why don't we just get Doc to tranq her the fuck out?" Waters replies with "That's a real good idea, drugging and kidnapping an American doctor...". The subject basically ends there. If they had, it would have made for a very short and pointless movie obviously. The possible reasoning could be that Waters had been getting "soft" for quite a while. It's unlikely he all of a sudden changed how he felt about doing missions as we saw in the movie. So he avoided giving a valid excuse to Red when he suggested tranquilizing Dr. Kendricks as he sympathized with her passion to stay and help the people. He wanted to save the people as much as she did, but it wasn't part of his mission. He was probably toying with the idea the entire trip to the helicopters. When they finally reached the helicopter he decided to follow through with his original mission. Then when they saw the devastation of the village, it was more than Waters could bear to have happen to the people he left behind.

Nearly two years after its first release on DVD, Sony published a so-called Director's Extended Cut that features a 20 minutes longer version. Several of the new scenes are Deleted Scenes, that could already be seen on the first release that have been integrated into the movie now.