goldox
Yes, if a passenger has a genuine reason, medical or otherwise to get off post-pushback, then our co SOP is to stop and interview the passenger in a galley. If medical, then it warrants an immediate return. A panic attack in my view AND especially a lo-co misconx, unless to the safety of the aircraft or detriment of the other passengers, does not constitute or warrant a return to stand.
If you want to get off bcos you will miss your connection, then tough, you're coming with us. Jump up and down, and complain about kidnapping will land you with a return to stand and a charge under the Air Navigation Order for being disruptive and failing to obey cabin crew, not withstanding that a lifetime ban from the airline.
Unfortunately there is no real or easy way of deplaning a passenger who decides to not to travel. Its a mandatory return to stand (probably remote) - offload grunt - rumage through the shellsuits downstairs to find said oiks bag - LMC LS and hope the guy in the tower popped a delay message on your ATC clearance, otherwise its a re-apply with late slot.
IF you get a panic attack or want to get off (within reason), you can do so right up to doors closed. Once doors are closed, so long as we dont start the pushback procedure, then you can get off. BUT............ your disembarkation WILL be annouced over the PA, very embarressing for you but highly amusing for us and other passengers (until they realise they are now delayed - to which the fun turns normally to irate angry passengers, fortunately directed to the oik who gets off)