I'm going to build off of Jason's notes (who is a classmate of mine apparently, we've never met! I'm Screenwriter MFA, you must be director?)

Anyway, yes, do read Hal's and Richard's books, or even Syd Fields' basic tome and/or Save the Cat. Remember that all grammatical and sentence structure rules apply as anywhere and nothing will get you a do not recommend pass faster than poor English skills. That said you may not speak English as a first language, and this is legit, just make sure a native speaker goes through it for you.
I think even beyond the passive usage of language you have some larger issues with the story telling on this page. There is a difference between "real life" and "reel life." The entire scene comes off very on the nose. Not to say that people can't say or do exactly what they mean, but in real life I doubt someone would approach a window, see their lover banging another dude, scream, and drop a ring box on the lawn while running away. There are about 100 different ways you could make this more tense and more dramatic and raise the stakes on conflict. Every scene has to have conflict and action should inform us about character. A man who screams, drops a ring box while running away isn't a man who abruptly sits in a room with a gun. Nor does a woman banging a jerk collapse on her lawn. Catching someone cheating is good, dramatic choice to raise conflict in a scene. Crying while holding a gun is also a good dramatic choice for conflict. Maybe try to think about these scenes and what drives one into the other in a more cinematic manner.
Spitball: John approaches the window (bring us with him, reveal the action to us in layers). He notices the car in the driveway that shouldn't be there. Suspicious, he peers through the dining room window where Mike is doing Mary on the kitchen counter, right next to the toaster John bought for her in the last scene! John drops the ringbox and picks up a rock. We're inside with the lovers when a rock crashes through the window. Confused Mary gathers herself in time to hear John's tires peel away. When she comes outside his car disappears around the corner and she spots the ring on the lawn. Numbly or coldly she picks the ring up. If Mike is still a jerk she tells him to shut up in a way that communicates she knows she made a mistake. Or maybe she didn't make a mistake and realizes it (John is nuts enough to go get a gun afterall).
The action of a jilted man throwing a rock through a window and running off tells us he might be a coward who would get a gun and not think clearly. It ups the conflict. Also you can give us something for John other than a phonecall. Stay off the phone if you can in a script, he may as well be having a conversation with a chair as cinematic as that is.

Don't be afraid to give us a little more and make it more cinematic and dramatic for the reader, exactly as it would look and be revealed to a camera and an audience, take a little more time with it. If you are a director try to think of the words cinematically, give us the meat of the visuals you're seeing in your head. The only time you will be able to get away with not making it cinematic for the reader is when you're planning on shooting it yourself, but if this is to be read for admittance into a program I would definitely try to make it as reader bait as possible.
Hope that helps!