Reliable way to wait for players in a function?

This question sounds weird and possibly even incredibly obvious-- but let me explain.

This script here, works in studio-- but as you know Roblox actually takes time to load the things I need in a server-- which creates the problem

local function RandomPlayer()
	local players = game.Players:GetPlayers()
	if #players > 0 then
		return players[math.random(#players)]
	end
end	

local FacePlayer = coroutine.wrap(function()
--	wait(5)	
	
	while wait(0.1) do
	
	local Plr = RandomPlayer()
		
	local Chr = Plr.Character
	
	local TorsoPos = Chr:WaitForChild("Torso").Position	
	
	local Gyro = Boss.Core.BodyGyro
	Gyro.CFrame = CFrame.new(Boss.Core.Position, TorsoPos) 
	Gyro.MaxTorque = Vector3.new(math.huge, math.huge, math.huge)
	Gyro.P = 999999
	end
end)

FacePlayer()

The problem is in the RandomPlayer() function-- I don't know how to write a check to make sure there are players to randomly choose as Roblox loads everything-- without having to just stop the script for 5 seconds or having ALL MY ATTEMPTS OF FIXING IT JUST TIME OUT AND STOP THE SCRIPT ANYWAY! >;0

Also this has a fine habit of breaking if your torso doesn't exist because you say-- fell off the map Ou0; Something that I'm also having a hard time writing a check for.

Yes, I know there are other things wrong with this-- but those problems I want to solve myself. For now I'd like help with actually waiting for players ;o;