well this is the script

game:GetService("UserInputService").InputBegan:connect(function(input,gameprocesed)
	if input.KeyCode == Enum.KeyCode.LeftShift then
		for i = 1,16 do
			wait()
			game.Workspace.Camera.FieldOfView = game.Workspace.Camera.FieldOfView + 1.6
			game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed + 1
		end
	end
end)

game:GetService("UserInputService").InputEnded:connect(function(input,gameprocesed)
	if input.KeyCode == Enum.KeyCode.LeftShift then
		for i = 1,16 do
			wait()
			game.Workspace.Camera.FieldOfView = game.Workspace.Camera.FieldOfView - 1.6
			game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed - 1
		end
	end
end)

game.Players.LocalPlayer.Character:WaitForChild("Humanoid").Died:connect(function()
	game.Workspace.Camera.FieldOfView = 70
	game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
	script.Disabled = true
end)