Excellent job! Just a couple things stuck out for me as out of character and discontinuous.
p.9. Bathroom--Marcus is squeamish. He doesn't seem like the kind of guy who would stitch his own wounds. He's cowering rather than fighting back. It is, IMO, totally out of his character. Then the jump to the Kitchen and suddenly time is restored? Because Alyssa is talking.
If you want the sense there are two planes of time co-occurring, there needs to be something that makes it distinctive. As a very stark example--stasis time is B/W while 'real' time is color. Of course, visually you can handle it as you wish, but it needs to be distinct. This threw me when I read it.
p12 - "and she swings the bat over her head" Did you mean the old neighbor's head or Alyssa's head?
This is the kind of story that when I watch it on TV, I wonder why the author didn't really fully utilize the device. So I'm going to lay it out from my perspective. Here is a guy who loves this sociopathic girl. He has a device that freezes time. He could use it to (1) move the old lady to safety (say, her bedroom free with a note to call the police) and/or (2) he could disarm his lover of the bat, gun and secure her until the police arrive. If he loves her, it makes no sense why he would kill her with such a powerful tool at his disposal. Especially since it's hinted that he used it to remove the clip from her gun.
I think I would close the scene with him comforting the old lady as the police arrive. All seems tidy until she breaks free, runs into the room and shoots at him. At the last second, he activates the unit as she pulls the trigger. He's sad and moves her body in the line of the bullet. He walks through the door and sees the police rushing toward the bedroom frozen. Once outside, he starts time again. He weeps and moves back to the engineer's house. He gathers up the blueprints, presses the stasis button and vanishes. Cut back to see the medics checking out the old woman and them bring Alisa out on a stretcher zipping up the body bag.
Okay. Now I KNOW this is a short with limited budget. But the point is, he has a device that stops time and he can only think to shoot her? He loves her. There needs to be a compelling reason for him to act outside of his nature, which to this point is pretty low key.
Perhaps on p12 she actually does fire at the woman after glaring at Marcus. Marcus freezes time and makes the switch. And your script can go on as before. I do think, if I were Marcus, I'd want to scoop up those blueprints, however.
This is really a very creative, inspired script and will make a fantastic short. Good luck with pre-production.