Constant Checking System?

So, without getting too technical, i have a script that pretty much plays out the game. It starts the round when 2 or more players are within the game, a random map is chosen. Along with a Killer & Officer. The players spawn within the map. And the killer & officer also spawn but with selected weapons.

I'm currently confused on how i can make a constant checking system, so if a player leaves when the map is spawning or when everything is chosen and players are about to be spawned, something happens, to the point where there is only 1 player left. The current script i have just STOPS when a player leaves and there is only 1 player left. No errors in output.

I HAVE tried something, but it doesn't work and takes up too much space. Please help. Thanks. :)

Also, when answering please stick with answer my question. I don't need people commenting on how dreadful or sloppy my code is.

------------------------Variables-------------------------------
minigames = game.Lighting.Minigames:GetChildren() -- Minigames Variable
round = ("default") -- Round Status
OfficerWep = game.Lighting.gun1 -- Officer Weapon
HitmanWep = game.Lighting.gun2 -- Hitman Weapon
message2 = game.Workspace.LobbyModel.Partmain.SurfaceGui.main -- The main GUI
message3 = game.Workspace.LobbyModel.Partmain.SurfaceGui.timer -- The Timer GUI
HitmanGUI = game.Lighting.HitmanGui
OfficerGUI = game.Lighting.OfficerGui
local sound = Instance.new("Sound")
sound.SoundId = "http://www.roblox.com/asset/?id=130802245"
sound.Parent = game.Workspace
------------------------Main-------------------------------




function playMusic()
    sound:play()
    wait(10)
end

function checkPlayers()
 if game.Players.NumPlayers == 1 then
    wait(2)
   end
end



while true do
    if game.Players.NumPlayers > 1 then
     if round == ("default") then --Checks if a round has recently ended
    print("Starting default round") --This will print the first time the server is started, i think.
elseif
    round == ("over1") then
    message2.Text = ("Round will start soon")
    wait(20)
end
        sound:stop()
        checkPlayers()
        message2.Text = ("Randomly selecting map...")
        wait(3)
        ---------------Random select Map-------------------------
        checkPlayers()
        ranGame = math.random(1, #minigames)
        gameChosen = minigames[ranGame]
        checkPlayers()
        message2.Text = ("Map Chosen: " ..gameChosen.Name)
        wait(3)
        gameChosenClone = gameChosen:Clone()
        gameChosenClone.Parent = game.Workspace
        checkPlayers()
        message2.Text = ("Map Chosen: " ..gameChosen.Name)
        wait(3)
        message2.Text = ("Randomly selecting Hitman & Officer...")
        checkPlayers()
        wait(2)
        ---------------Random select hitman and officer----------
        checkPlayers()
        Players = game.Players:GetPlayers() -- Add all players to Plrs table
        killer = Players[math.random(1,#Players)] -- Get a player, this player is defined under Players
        hero = Players[math.random(1,#Players)]
    ---------------Checking System----------
    checkPlayers()
    if killer == hero then -- Checks if the selected killer/hero is the same, and if so changes it so its not
        repeat
        killer = Players[math.random(1,#Players)]
        wait(1)
        hero = Players[math.random(1,#Players)]
        until
        killer ~= hero
    print("The Hitman is " ..killer.Name)
    print("The Officer is " ..hero.Name)
        wait(1)
             end
       round = ("starting")
       ---------------Teleport players to selected map----------
       spawns = gameChosenClone.Spawns:GetChildren()
       checkPlayers()
    message2.Text = ("Round in progress...")
    for i,v in pairs(game.Players:GetPlayers()) do
        name = v.Name
        check = game.Workspace:FindFirstChild(name)
        if check then
            checkHumanoid = check:FindFirstChild("Humanoid")
            if checkHumanoid then
                check:MoveTo(spawns[i].Position)
            end
        end
    end
       OfficerWep:Clone().Parent = hero.Backpack -- Gives the Officer Gun1
       HitmanWep:Clone().Parent = killer.Backpack -- Gives the Hitman Gun2
    --------------Tutorial GUI---------------------
    OfficerGUI:Clone().Parent = hero.PlayerGui
    HitmanGUI:Clone().Parent = killer.PlayerGui
    wait(15)
    hero.PlayerGui.OfficerGui:Destroy()
    killer.PlayerGui.HitmanGui:Destroy()
    HeroDied()
         else
      playMusic()
    message2.Text = ("There needs to be more than 1 player to start")
     end
    wait(1)
end