Key still not working/broken?

As you can see my problem is that once the player presses the shift key he should follow the mouse and once he presses it again he should stop following the mouse and move normally after this, but it seems that if i press any key but shift it deactivates the player following mouse script again after i activate it with shift again. You can try this script yourself by putting

local mode = 0 -- 0 = default, 1 = battle.
local gyro = Instance.new('BodyGyro')
gyro.maxTorque = Vector3.new(1400000,1400000,1400000) 
wait()
local cFrame = CFrame.new(0, 0, 0)
local torso = player.Character.Torso

mouse.KeyDown:connect(function(key)
	if mode == 0 then
gyro.Parent = game.Lighting
	if string.byte(key) == 48 then
	mode = 1
	end	
end

	if mode == 1 then
gyro.Parent = torso
	if string.byte(key) == 48 then
	mode = 0
	end
end

game:GetService("RunService").RenderStepped:connect(function()
local position = mouse.Hit.p
local setPosition = Vector3.new(position.X, torso.Position.Y, position.Z)
local direction = (setPosition - torso.Position).unit
cFrame = CFrame.new(torso.Position, torso.Position + direction)
gyro.cframe = cFrame
end)

Im pretty sure your problem is where you check "if" mode == () then: use elseif in order to run both of them if the first one is incorrect.

local mode = 0 -- 0 = default, 1 = battle.
local gyro = Instance.new('BodyGyro')
gyro.maxTorque = Vector3.new(1400000,1400000,1400000) 
wait()
local cFrame = CFrame.new(0, 0, 0)
local torso = player.Character.Torso

mouse.KeyDown:connect(function(key)
    if mode == 0 then
gyro.Parent = game.Lighting
    if string.byte(key) == 48 then
    mode = 1
    end 
end

   elseif mode == 1 then
gyro.Parent = torso
    if string.byte(key) == 48 then
    mode = 0
    end
end