Script that Picks a Random Player?

I'm a beginner at scripting but it may be something like

_G.getRandomPlayer = function()
local pl = game.Players:getPlayers()
return(pl[math.random(1, #pl)])
end

Put that in a script and all scripts in the game can use it like this:

getRandomPlayer().Character:BreakJoints()

would kill a random person. But in your case just use it to change them as killer maybe change their team to killer or give something in backpack Whatever you want the killer to have/do