I think many try to some extent, but we don’t exactly leave a lot of room to manoeuvre. Classrooms don’t seem to work without substantial conformity, bills have to be paid, employers catered to, and even just plain social pressure to not stray too far off the beaten path.
Not if he’s off screen. It’s only a visual cue if it’s captured by the video.
If you have a separate video of the guy falling over dead, you can use that video to get a window of time to view in the other video, but one video that captures only parts of the scene can easily leave you with no visual cues.