Studio crashes when a round loads?

I know the title may be vague, but there wasn't really any better way to explain it. Basically, I'm making a game that works in a round system (ROBLOX version of Trouble in Terrorist Town, if that helps). That is, pre-game, in-game, post-game, repeat.

But I noticed an issue. I made a server with four players in Studio and it crashes when the round ends, after a certain message.

Here's the snippet of code the error should be around:

local mapDir = game.ServerStorage.Maps
	
	local newMap = mapDir:GetChildren()[math.random(#mapDir:GetChildren())]
	
	local m = Instance.new("Message",game.Workspace)
	m.Text = "New game starting with the "..newMap.Name.." map..."
	
	wait(5)
	m:Destroy()
	
	newMap:clone().Parent = game.Workspace.Map
	
	local newTraitors = choose_traitors(2)
	
	for a,b in pairs(playerDir:GetChildren()) do
		local val = Instance.new("IntValue",b)
		val.Name = "traitor"
		for c,d in pairs(newTraitors) do
			if b == d then
				val.Value = 1
				break
			end
		end
	end
	
	for a,b in pairs(playerDir:GetChildren()) do
		if b:findFirstChild("dead") then
			b:findFirstChild("dead").Value = 0
		end
	end
	
	in_game = true
	script.in_game.Value = 1
	
end

The script crashes the pseudo-server after the m.Text = "New game starting with the "..newMap.Name.." map..." message displays for 5 seconds.

(if you need the choose_traitors() function, ask)