If this comedy happens, then Vikramshila will return @ BGP for PM, maybe as Dumka Bhagalpur Passenger, approx @ 5 PM to reach BGP @ 8 PM.
BGP Dumka Pass may run @ 4 AM to reach Dumka @ 7 AM & return @ 7:45 AM as Vikramshila to reach BGP @ 10:50 AM & after LC, move to ANVT @ 11:15 AM!!