great composition worthy of a quiet scene in a Sci-Fi blockbuster

That was quite interesting!

I'm currently trying to write a song in A locrian, and I feel like it's starting to come together now. I wrote a motif for the chorus that mainly just spells out the tonic chord (A, C, Eb) with an extra D note passed by to connect the C and Eb. So I use the flat 5th and the tonic note a lot in the chorus to hopefully establish the locrian sound. In the verse I instead use the flat 2nd alternating with the root note and some other extra notes to hopefully achieve the locrian sound in a slightly different way. My idea with that was to get some clear distinction between the verse and the chorus, and to keep that Eb as my highest note. And I play that entire melody over a pedal note, or rather a frequently repeating 8th note. Maybe more of a drone note, but whatever. I haven't made the bridge yet, but I quite like what I've made so far! I dunno why, but I feel like I'm at less risk of making it sound like its relative major when I use A locrian. Because when I tried to use B locrian it felt much harder to avoid it ending up sounding like C major. Maybe because I'm just less familiar with Bb major, but I dunno. That said, while I do use the F note here and there in the verse (which wants to resolve to Bb) I never follow it up directly with a Bb, other than as a passing note, and I think that way I avoided it sounding like Bb major. Basically I think you give good advice about really hammering through that tonic note throughout the piece in one way or another, and to have (some or more) of the melody spell out the tonic chord. Also making some use of that flat 5th and/or flat 2nd that are so characteristic of the locrian mode. I think following those steps does really help me bring forth that locrian sound.

Locrian is far too underated

Your locrian Composition sound like a soundtrack for a murder mystery where someone has just been murdered and now everyone is wondering who the killer is.