Director Matthew Vaughn is famously fond of action sequences that look like they were shot all in one take — filmed in a very specific way designed to convince you that they're real, no matter how impossible that would be.
In the first Kingsman film, this happened in the church, and io9 named it the best movie moment of 2015. In Kingsman: The Golden Circle, the same kind of thing happens again, in a briefcase battle near the end of the film. This behind-the-scenes video shows you how it went down, and how labour-intensive it was to pull off. It's pretty incredible (but if you haven't seen the movie, it's certainly a spoiler).
Kingsman: The Golden Circle is now out on Blu-ray.