An interesting, multi-perspective compilation put together, shows a Russian, "Z" marked BTR-4 lighting up the Azovstal steel plant in Mariupol.

Although we have no clarification on this, the footage claims the BTR was captured by Ukrainian forces, and the gunner shown in the footage is actually Ukrainian. The only questionable argument I have to combat this is why would they be shooting at their own territory? Over the past several weeks, we have seen Russian forces storming through Mariupol, and have seen a significant amount of air-to-surface bomb runs in this specific area.

To go along with the stated claims, were they engaging the newly, Russian occupied territory? It's unfortunately impossible to tell, as no visible targets are present in the footage. Regardless, multi-perspective footage like this is very cool from an analysis standpoint.

I'll leave it to you guys in the comments below. Let me know if you spot anything I have maybe overlooked during analysis.