Bugged but I don't know why?

Ok so I'm making a script where "A" rotates the character counter-clockwise and "D" clockwise, but there is a bug causes the player to wiggle extremely quickly.

local turnSpeed = 7.5

USI.InputBegan:connect(function(inputObject)
	if player.Character then
		while inputObject.KeyCode == Enum.KeyCode.A do
			root.CFrame = root.CFrame*CFrame.Angles(math.rad(0), math.rad(turnSpeed), math.rad(0))
			wait()
		end
		while inputObject.KeyCode == Enum.KeyCode.D do
			root.CFrame = root.CFrame*CFrame.Angles(math.rad(0), math.rad(-turnSpeed), math.rad(0))
			wait()
		end
	end
end)

USI.InputEnded:connect(function(inputObject)
	if player.Character then
		while inputObject.KeyCode == Enum.KeyCode.A do
			root.CFrame = root.CFrame*CFrame.Angles(math.rad(0), math.rad(-turnSpeed), math.rad(0))
			wait()
		end
		while inputObject.KeyCode == Enum.KeyCode.D do
			root.CFrame = root.CFrame*CFrame.Angles(math.rad(0), math.rad(turnSpeed), math.rad(0))
			wait()
		end
	end
end)

Sometimes the person isn't wiggiling other times he goes really fast, and sometimes he moderitly. How can this be fixed?

Figured it out:

USI.InputBegan:connect(function(inputObject)
	if player.Character then
		if inputObject.KeyCode == Enum.KeyCode.A then
			turnSpeed = turnSpeed + 7.5
		end
		if inputObject.KeyCode == Enum.KeyCode.D then
			turnSpeed = turnSpeed - 7.5
		end
	end
end)

USI.InputEnded:connect(function(inputObject)
	if player.Character then
		if inputObject.KeyCode == Enum.KeyCode.A then
			turnSpeed = turnSpeed - 7.5
		end
		if inputObject.KeyCode == Enum.KeyCode.D then
			turnSpeed = turnSpeed + 7.5
		end
	end
end)
while character do
	root.CFrame = root.CFrame*CFrame.Angles(math.rad(0), math.rad(turnSpeed), math.rad(0))
	wait()
end

I figured out that problem was that multipul anlges were being set but not all at the same time, causing the character to wiggle. So I made it where only one angle was changed for the whole script rather than the whole time.