ThinkSpace Education, 5 Days of Christmas, Day 1

Still a newbie, still please be gentle!
So, composer extraordinaire @GuyMichelmore at #ThinkSpaceEducation is doing a #5DaysOfChristmas thing. Day 1 was to score the movie scene provided. Note: I do not own the copyright to the movie scene, but I do own the copyright to this (my) score.
This is the first time I've actually tried creating music for a scene. As you can see my attempt is pretty simple! I've tried to line-up way-points (as Guy calls them) with the score, but more than that have tried to match some things up exactly. So, for example, the cello hits with each of her steps at the beginning of the scene. (Given more time I could get these absolutely bang on). Obviously it's a suspense/thriller scene, but it's interesting that it's quite easy to slip from suspense into horror (dissonant notes, etc) so I tried not to do that. I went with Cm because when she presses the keys with the gun she's effectively running up the key of C (major). Quick note - The sound effects were all on the video already, except the heartbeat at the end which is mine.
Constructive criticism welcome!