EI engineers both sides of the pond definately take maintenance and faults seriously, no matter how big or small the problem is. I have been on the receiving end of this on a few occassions when i worked for them at JFK, if they can't replace the part there n then, simple their either cancel the flight or charter in another airline to operate on behalf of them, under no uncertain circumstances would an EI engineer allow that aircraft to leave the ground with a problem. Ive seen problems as small as a few seat covers needing replaced being a reason for delaying the flight when we ran out of stock of them at the airport and further supplies were sourced from Jerhico N America Head Office. As EISNN said they have probably the best reputation or one of the best reputations in the industry for maintenance and safety. Hate when people just suggest its a maintenance issue because a flight has diverted, obviously there are other many factors other than maintenance that could cause a diversion, in this case its medical related.