WAIT NO LIKE HOW DO U GET THE SCENE TO KILL EM AT ALL IT NEVER SHOWS UP FOR ME 😭
There are lots of options to do it in the prologue. The second option as you find the altercation is an instant kill, as are the second and third options for the option after that (there's a lot of branching here lol).
If you choose to talk to the guy or throw him down first, there are also options that state MC's intent to kill him. You can't kill anybody else in-game--yet.