RedTBar - perhaps we should look at this from a pilot's point of view.
Do you know anything about ETOPS?
If not allow me to add my 2c worth.
For all A330 aircraft throughout the world a U/S APU is not a critical failure and therefore will not prevent an ETOPS dispatch.
This means that after a critical failure in flight (such as an engine failure) the aircraft can legally and safely fly for a further 180mins to land at an adequate airfield (in this case DPS).
Please by all means go to the Airbus website and have a look at the number of IFSD (inflight shutdowns) that the aircraft/engine type is required to have been proven on.
Straight from the Airbus website on ETOPS:
"Propulsion system reliability is the most vital aspect of ETOPS and must
be sufficient to ensure that the probability of a double engine failure from
independent causes is lower than defined limits (this requirement
establishes a maximum In-Flight Shutdown (IFSD) rate of 0.02/1000
engine hours for 180-minute ETOPS)."
Hope this allays your fears.