It's the first anniversary of the HIMARS hit on a huge ammo dump at Krasnyi Luch in Eastern Ukraine. A group of young Russians had just finished unloading a truck, not too far from the dump and were taking a break, with some music playing; one of them was wearing a GoPro or the like around his neck or loosely pinned to his shirt, and that's how we came to have video of the next 11 minutes.
One thing that does need a bit of explanation is the point, early on, where everyone piles into the truck. There's a bit of discussion, then they all fall silent -- then spill out of the truck. Last year a reddit commenter did some geolocation and discovered that the truck was sitting in a cul-de-sac and that the only way out would take them toward the ammo dump, not away. You can see the realization settle on the crew as they watch the fireworks spread.
The description given in Russian google-translates to "Point-U hit warehouses with ammunition!!! Thank God our guys are alive!!"
Without further spoilers, here is that video.