Had same situation while flying F with LX (A340) HKG-ZRH 1 year ago.
On take off run, suddenly everything stops, lights, engines, all off.
Stuck in the middle of the RWY and surrounded by fireman checking that everything is ok with the engines.
We got back to the gate, and then decided to deplane. The reason: I'm flying F to ENJOY the flight not to SUFFER for 12 hours remembering all the Air Crash investigation episodes I've watched, plus I missed my connection in ZRH and the next flight was about 10 hours later, so I didn't fancy to wait for 6 more hours in ZRH, or do whatever reeschedulling involving several transfers to get to my destination.
In this case we were several pax wanting to leave the aircraft. LX made it clear: if you leave, and if your ticket is not refundable/changeable: you loose it.
I just confirmed that I wanted to leave and LX arranged my luggage to be deplaned etc in about 30 minutes time. I don't think anybody else left, but for sure the whole aircraft was inmersed in tension during the second take off. AF 447 and JK's crash were quite recent at that time, so that might have impact both the pax and the crews response to the situation.

CX not wanting to let you out seems a very propable case of kiddnaping, specially as it is perfectly possible to get the bags etc out of the plane while they do the tach checks. You don't want to fly, then that's it, I don't see how they can force you to fly, even more, keeping an anxious pax in the aircraft against its will isn't certainly good practice for avoiding air rage. In any case I supouse if you let the crew know firmly that you do not want to stay aboard they would try to get you out asap so as to avoid a "contagion" to other pax having doubts about flying or not flying.

If I were you I would send a complaint to CX and ask for a clarification on their policy for dissembarking pax. Specially as you were flying F. (not that Y pax do not deserve the right to jump out the ship, but I would expect less resistance from the crew for F pax.)

And btw, I was quite happy to have stayed in HKG, had a good sleep in a proper bed and flew a couple of days later on LH fully enjoying my flight.