proof of concept

local remote = game.ReplicatedStorage.YourRemote -- the remote which will be exploited.
local code = 0 -- this is where we store the code when its obtained.

local OldNC;
OldNC = hookmetamethod(game, "__namecall", function(Self, ...) -- hook __namecall.
    local Args = {...} -- put arguments into a usable table for later.
    local method = getnamecallmethod() -- get the method for later.

    if not checkcaller() then -- prevent infinite looping and detection by game anti-cheat.
        if method == "FireServer" and Self == remote then -- checking if the method is :FireServer and if it was called on the remote of which we want the security code.
            code = Args[1] -- assuming code is the first entry, obviously this can be different but this is a short example script so it doesnt matter.
            print("Obtained code: "..tostring(code))
            return OldNC(Self, ...) -- let the original :FireServer call go through to prevent issues.
        end
    end
    return OldNC(Self, ...) -- let the original :FireServer call go through to prevent issues.
end)