There are major problems with the script formatting. You misuse the slugline. The problem is that you are trying to direct from within the script. In a spec script, you should be telling a story, not trying to play director or DP. You may think you're just giving location information, but really it's directing from inside the script. For example, p. 6, "OUTSIDE CAR: ... INSIDE CAR: ...". You should simply describe the scene not imply where the camera is located. Also, you abbreviate the locations and assume that "INT. REMOTE OUTPOST" suffices. It doesn't. You need to label each of those different locations. Is the hallway on p.3 the same one as on p.4? As an AD, I need to know how many unique locations are needed. As a general guide, only use that for unique locations. Even then, you are never wrong to use a full slugline.
On p. 4, it feels like the "HALLWAY" takes place later. There is a time shift between when the boss hangs up and we switch to following him. On p. 6, you have continuous. Continuous is NEVER used as a time descriptor, it is strictly spatial. So when is this taking place? Also, you overused CAPS. You don't need them for sounds as you used them. Then you put in "End Teaser".
Outside of all other issues, the script's formatting is distracting and needs serious revision. As Maz mentioned, there are development flaws in the characters. You bring in Miranda and her colleague. He confronts her then you re-state the obvious. The reference to "going" is nebulous and a waste of time. Make it a strong relevant statement and make that clear rather than nebulous. So much could be done to create a clearer sense of the characters and their dread. It just felt brushed over. So when I got to p.8 and you said that was the teaser, I had to disagree. I wasn't teased.
From p.9 forward the characters were hodge podge and pretty flat and stereotypes. I'm not sure it works. I didn't understand the jump once the guard Dan appears in the door. It was like a set of images only loosely threaded together. I stopped reading at p. 9. I never got a good sense what this was about or who the main players were. This needs to be seriously rethought--format, character and story development need to spot on in the first 10 pages. Good luck.