CBC pax interviews state that the cabin crew took their bags and left the A/C on arrival at the gate. Pax were left onboard to fend for themselves.
Quite odd, and contrary to Regs if this is the case, to leave 400 plus pax onboard an A380 with no crew, especially if fumes on board suspected??
British Airways flight diverted to Vancouver after cabin crew becomes ill - British Columbia - CBC News