Laravel persist $request->flash old() session - forms

Question

So, I've build in functionality which redirects the logged in user to a pincode screen after 10 minutes of inactivity, when the user enters the correct pincode he or she is redirected to the page where he or she was navigating to.. So far so good but...
Imagine the user is filling out a form and waits ten minutes before hitting the submit button and is then redirected to the pincode page, after inputting the correct pincode he is on the form again but all data on it is gone.
What I want is to remember all the filled data, I've tried it via the old() method but that only persists for one request.
PincodeCheck Middleware
if($difference_in_minutes > config('pincode.lifetime')) {
return redirect()->route('pincode')->withInput();
}
PincodeController
public function index(Request $request)
{
// $request->old() is holding the values
return view('pincode.index');
}
public function unlock(Request $request)
{
// This is the after submit function, $request->old() is empty here
if(Hash::check($request->pincode, auth()->user()->pincode) == true) {
$request->session()->put('pincode-timestamp', date('U'));
$path = config('app.homeroute');
if($request->session()->has('intended.get.path')) {
$path = $request->session()->get('intended.get.path');
}
return redirect($path);
}
return redirect()->route('pincode');
}