A bug in my script i can't seem to understand why it happens, why?

in short, i made a script that lets you run when pressing shift, and lets you walk when you let go.

you are able to run when an Intvalue is more than 0, and it increases every second by 1 when not running.

However, if you press shift two times under a second, the intvalue increases by 1 TWICE every second. from my understanding , the script malfunctions and runs the same line twice.

(the main bug starts at line 30)

repeat wait() until game.Players.LocalPlayer
local running = false
local amount = game.StarterGui.run.Value.Value

local function stoprunning()
	game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 11 
end

m = game.Players.LocalPlayer:GetMouse()


m.KeyDown:connect(function(key)
	if key == "0" and running == false then 
		print("Running")
		running = true
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 22
		while running == true do
			game.StarterGui.run.Value.Value = math.clamp(game.StarterGui.run.Value.Value - 1, 0, 100)
			local amount = game.StarterGui.run.Value.Value
			print (amount)
			wait(0.1)
			if amount == 0 then
				game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 11
			end
		end
			
	end
end)

m.KeyUp:connect(function(key)
	if key == "0" and running == true then
		running = false
		local amount = game.StarterGui.run.Value.Value
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 11 
		while running == false do
			local amount = game.StarterGui.run.Value.Value
			game.StarterGui.run.Value.Value = math.clamp(game.StarterGui.run.Value.Value + 1, 0, 100)
			print(amount)
			wait(0.9)
		end
	end
end)

You should always be careful of putting while loops in event handlers: every time someone taps "0" , you start a new while loop, causing your code to run 2x (or more if they keep tapping "0" in the right way).

Two possible fixes:

• Add additional variables to make sure that you don't enter into the while loops if they're already being run
• Whenever you start the while loop, increment some variable. Stop executing the loop if this variable is changed (since this means that another thread has started running the while loop and the current thread is now the "old" one).