Can someone help me with this combined sprint (shift and double tap w) script?

I tried to combine minecraft sprint script and shift sprint script but there's a problem. It screws up my walkspeed and the camera's field of view when i did both double tapping w and holding shift and release w before releasing shift.

I've removed the animations the script gave me, renamed the variables and added more conditions to separate both functions but it doesn't seem to work.

It'l be nice if someone can fix it.

And here's the script:

local mouse = game.Players.LocalPlayer:GetMouse()
local wrunning = false
local shiftrunning = false
local s = ""

mouse.KeyDown:connect(function (key)
    key = string.lower(key)
    if (key == "w" or key == "") and string.byte(key) ~= 48 then
        s = s.."w"
        delay(0.2,function ()
            if s ~= "ww" then
                s = ""
            end
        end)
        if s == "ww" then
            s = ""
            wrunning = true
            local wkeyConnection = mouse.KeyUp:connect(function (key)
                if key == "w" or key == "" then
                    wrunning = false
                end
            end)
            local fov = game.Workspace.CurrentCamera.FieldOfView
            for i = 1,5 do
                game.Workspace.CurrentCamera.FieldOfView = (fov+(i*2))
                wait()
            end
            local walkspeed = game.Players.LocalPlayer.Character.Humanoid.WalkSpeed
            game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = walkspeed +8
            repeat wait () until wrunning == false
            wkeyConnection:disconnect()
            game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = walkspeed
            for i = 1,5 do
                game.Workspace.CurrentCamera.FieldOfView = (fov+10-(i*2))
                wait()
            end
        end
    end
    if string.byte(key) == 48 and key ~= "w" then
        shiftrunning = true
        local shiftkeyConnection = mouse.KeyUp:connect(function (key)
            if string.byte(key) == 48 then
                shiftrunning = false
            end
        end)
        local fov = game.Workspace.CurrentCamera.FieldOfView
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (fov+(i*2))
            wait()
        end
        local walkspeed = game.Players.LocalPlayer.Character.Humanoid.WalkSpeed
        game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = walkspeed + 8
        repeat wait () until shiftrunning == false
        shiftkeyConnection:disconnect()
        game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = walkspeed
        for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (fov+10-(i*2))
            wait()
        end
    end
end)

Thanks.