I’m still not sure that I fully understand the question, but an early version of this sort of video – I believe from the same MIT lab – showed light visibly traveling though a Coke bottle filled with a milky fluid, and IIRC the camera was indeed more or less perpendicular to the direction of light travel. You could literally see the light beam, in slow motion, traveling through and reflecting around the inside of the bottle.
You can’t really have a camera running at a trillion FPS. The way they did it was to repeatedly strobe the light, and take pictures over and over again at very precisely timed intervals. The fact that the light emissions were repetitive was key to this experiment, and allowed them to cleverly create what was effectively “capturing the actual travel of a light beam”.