Locking the mouse at one point

I have a third person camera, and it currently locks the player from zooming in or out, and it also makes the person follow where the mouse is going. What i need now is to make the mouse lock at one position on the screen. How would i start ? Here is the Cam script

local abs = math.abs

local distance = 5
local zoom = 70
local sensitivity = 0.25
local height = 1

local player =  game.Players.LocalPlayer
local mouse = player:GetMouse()
local camera = Workspace.CurrentCamera

while not camera do
        Workspace.Changed:wait()
        camera = Workspace.CurrentCamera
end
while not mouse do
        wait(0.5)
        mouse = player:GetMouse()
end

wait()

local char = true
local gyro, head, torso

camera.CameraType = "Scriptable"
camera.FieldOfView = zoom

while wait() do
        if char ~= player.Character then
                char = player.Character
                while not char do
                        char = player.CharacterAdded:wait()
                end
                torso = char:WaitForChild "Torso"
                head = char:WaitForChild "Head"
                gyro = torso:FindFirstChild "lookatmouse" or Instance.new "BodyGyro"
                gyro.maxTorque = Vector3.new(0, 7000, 0)
                gyro.cframe = CFrame.new(0, 0, 1) + torso.Position
                gyro.Name = "lookatmouse"
                gyro.Parent = torso
        end
        local hit = mouse.Hit
        if mouse.Hit.p.magnitude ~= 0 then
                local objhit = torso.CFrame:pointToObjectSpace(hit.p)
                local pos = head.Position + Vector3.new(0, height, 0)
                local focus = CFrame.new(pos)
                local vec
                if abs(objhit.x) > objhit.z and
                        (objhit.x/objhit.y)^2 + (objhit.z/objhit.y)^2 > 1 then
                        vec = mouse.Hit.p - pos
                else
                        vec = camera.CoordinateFrame.lookVector
                end
                pos = pos - vec.unit * distance
                camera:Interpolate(
                        CFrame.new(
                                pos,
                                vec + pos
                        ),
                        focus,
                        sensitivity
                )
                gyro.cframe = mouse.Hit
        end
end