What if QM2 ship issue mid-Atlantic on crossing?

Hello Mr. Shanks! Thanks for being 'here' today for Q&A
We are loyal Cunarders (Platinum level); our most recent trip was a fabulous Eastbound crossing on QM2 in late November, 2012.
The recent unfortunate events on Carnival (Triumph fire & the Splendor fire a few years back) coupled with our recent (wonderful) crossing made me think about if an ocean liner like Queen Mary 2 could be so disabled in mid-ocean - and what sort of contingency plans could exist to cope if something so difficult happened far from shore.
As a purpose-built ocean liner, I would think that QM2 would have more back up capabilities than a cruise ship would - that the ship's design would have considered the fact that it would spend quite a bit of time so far from land & have some additional contingencies considered.
I am not a nervous sailor at all, but having seen the unfortunate Triumph events play out so soon after we were on a QM2 transatlantic crossing did make me think about back-up systems and contigency planning on QM2? Can you share some perspective? Thank you!

Rest assured that Queen Mary 2 was designed to cross the Atalantic and the questions you raise were very much taken into consideration in that regard.Best Regards. Peter