Sadly the T4 arrivals processing facility is no longer used, effectively decommissioned and all arrivals processing is done in TBIT even for planes arriving at T4 (AA from NRT for example); pax walk through a sterile underground tunnel from T4 to TBIT (and then walk back to T4 if departing from there ... quaint having same terminal arrival and departure be in different terminals). QF decided to move 107 arrival over to TBIT instead of doing this nonsense. Only AA lost its arrivals facility (not enough pax), DL and UA and NZ still have theirs in T5, T6 and T2 respectively.