Your painting of the firefighters is unique. It conveys a sense of camaraderie. The lines in the painting seem to draw the viewer toward the face masks. The two firefighters are leaning in toward each other, creating some interesting shapes.
If the face masks (or the meeting of face masks) are your intended focal point you could strengthen that area by enhancing reflections and/or contrast.
Another element of composition that you might want to improve would be the bottom of picture. The right hand figure's foot is dropping off the page. Perhaps moving the figures back a bit and grounding them with shadows??
Would an analogous color scheme on the uniforms help to increase interest and lead the eye through painting?
The painting shows technical skill - textures, detail, etc.
Overall very interesting painting.