Is there a way to cancel a function while it is running?

So I want to cancel this function so when all the players die but how can I cancel a function tho?

function StartGame()
    ChooseGame()
    print(rm)
    game.ReplicatedStorage.PlayersAlive.Value = game.ReplicatedStorage.NumPlayers.Value
    for i,v in pairs(game.Players:GetChildren()) do
        v.Backpack.inGame.Value = "Game"
    end
    game.ReplicatedStorage.GameStatus.Value = "Game"
    if rm == 1 then
        game.ReplicatedStorage.GameStatus.Value = "Game"
        local WaterRunMap = game.ServerStorage.WaterRun:Clone()
        WaterRunMap.Parent = game.Workspace
        game:GetService("ReplicatedStorage").GameTime60:Fire()
        game:GetService("ReplicatedStorage").WaterRun:FireAllClients()
        wait(2.5)
        for i,v in pairs(game.Players:GetChildren()) do
            v.Character.HumanoidRootPart.CFrame = CFrame.new(-207.5, 17.5, 151.5)
        end
        for t = 60,0,-1 do
            game.ReplicatedStorage.GameTime.Value = t
            wait(1)
        end
        EndGame()
        Intermission()
    elseif rm == 2 then
        game.ReplicatedStorage.GameStatus.Value = "Game"
        local BombBombRainMap = game.ServerStorage.BombBombRain:Clone()
        BombBombRainMap.Parent = game.Workspace
        game.ServerScriptService.BombRain.Disabled = false
        game:GetService("ReplicatedStorage").GameTime60:Fire()
        game:GetService("ReplicatedStorage").BombBombRain:FireAllClients()
        wait(2.5)
        for i,v in pairs(game.Players:GetChildren()) do
        v.Character.HumanoidRootPart.CFrame = CFrame.new(-43, 2.5, 27)
        end
        for t = 60,0,-1 do
            game.ReplicatedStorage.GameTime.Value = t
            wait(1)
        end
        game.ServerScriptService.BombRain.Disabled = true
        EndGame()
        Intermission()
    elseif rm == 3 then
        game.ReplicatedStorage.PlayersAlive.Value = game.ReplicatedStorage.NumPlayers.Value
        game.ReplicatedStorage.GameStatus.Value = "Game"
        game:GetService("ReplicatedStorage").GameTime120:Fire()
        local SwordFightMap = game.ServerStorage.SwordFight:Clone()
        SwordFightMap.Parent = game.Workspace
        game:GetService("ReplicatedStorage").SwordFight:FireAllClients()
        wait(2.5)
        for i,v in pairs(game.Players:GetChildren()) do
        v.Character.HumanoidRootPart.CFrame = CFrame.new(2, 5, 80)
        end
        for t = 120,0,-1 do
            game.ReplicatedStorage.GameTime.Value = t
            wait(1)
        end
        EndGame()
        Intermission()
    --[[elseif rm == 4 then
        local PlatformRunMap = game.ServerStorage.PlatformRun:Clone()
        PlatformRunMap.Parent = game.Workspace
        if NumPlayers.Value == 2 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 3 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 4 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 5 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 6 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 7 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 8 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 9 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 10 then
            print("PlaceHolder")
        elseif NumPlayers.Value == 11 then -- Sometimes roblox's servers can go 1 player over max So this is for that player 
            print("PlaceHolder")
        elseif NumPlayers.Value == 1 then
            print("Not Enough Players for gamemode!")
            print("Ending game!")
            PlatformRunMap:Destroy()
        end
        --]]
        elseif rm == 4 then --This Map is disabled Because it is a wip
        game.ReplicatedStorage.PlayersAlive.Value = game.ReplicatedStorage.NumPlayers.Value
        game.ReplicatedStorage.GameStatus.Value = "Game"
        local LaserTagMap = game.ServerStorage.LaserTag:Clone()
        LaserTagMap.Parent = game.Workspace
        wait(2.5)
        for i,v in pairs(game.Players:GetChildren()) do
            v.Character.HumanoidRootPart.CFrame = CFrame.new(104, 7.59996033, -35)
        end
        game:GetService("ReplicatedStorage").LaserTag:FireAllClients()
        wait(10)
        for t = 120,0,-1 do
            game.ReplicatedStorage.GameTime.Value = t
            wait(1)
        end
        EndGame()
        Intermission()
    elseif rm == 6 then --This Map is disabled Because it is a wip
        local SewersMap = game.ServerStorage.WIPSewers:Clone()
        SewersMap.Parent = game.Workspace
    end
end

I want to cancel this function