Sometimes, I get sidetracked watching the costumes, looking for interesting details or 'how did they do that' moments. But the video also showed us the realistic blocking; the fighting or wading through water in costume ... felt cold to me and I shuddered, ha. But, also the small movements, like the knife across the throat blocking - repeating it until it looks just right on camera. The floating camera is actually a camera mounted on a crane-like arm called a jib; and when you see the camera mount with the camera operatior slide on a set of rails, that sliding unit is called a dolly track, the camera and operator sit on the dolly. But, as you have seen, cameras can pretty well be mounted anywhere, even in the back of a pick-up truck; and now with drones ... don't get me started.
Watching stunts is amazing but also dangerous, and often stunts are filmed away from the general crews, for safety. Cameras are usually mounted wherever they can remain hidden from view in order to catch footage of the stunt from as many angles as possible. The small explosions in the walls are small explosive squibbs embedded into the inside of the wall, so the wall explodes outwardly and as realistic as possible. Professional Special Effects technicians must train and achieve a certificate before they are employed by major studios for this work, and the independent films I have worked on always seek a certified professional before including them as crew. In the special effects game, knowledge is only half the deal - the training and certificate, seal the deal.
This before and after video helps costumers realize how best to support the actors; and if we're working as on-set dressers, to remember never to laugh or hint that the actor looks silly. I'm sure we've all 'sang into our brush', pretending it is a microphone and we're singing to a vast crowd - and we feel embarassed or silly if caught. Professional actors draw huge energy from their wardrobe crew, to help them maintain the concentration needed to convey a character, especially when only a green screen is behind them, and not the furry beast, or nasty explosion. So, now you can go out there, and be the best costumer you can be, and fully support this incredible work that we do; and those amazing performers.