Unable to access $user or $application.user variable in the layout

Summary:

Hi Everybody.

I have got a requirement to create a custom field in the HrHelpDeskRequest layout and its value would depend on the user that is currently accessing the form. I have been trying and trying but can't figure out how could an action chain in the layout access $user variable and associated property like $user.userId. I tried to use this variable in vbEnter Listener but this variable always comes out as undefined (console.log($user)) . The page which hosts this layout helpdesk/employee/service-request-create/service-request-create-start page is able to view $user and even $application.user.userId, is there a way to pass this variable from page into