Maybe you should spend a little time rereading Tupe
It does protect what you have, not what you wish for.
If BMI do become merged with BA, after LH have finished the current restructuring, and after IAG have done their bit to reshape the remnants, then any merger will respect current positions, pay and terms and conditions.
It will not allow for enhanced T&c's and elevated pay, if BMI are ring fenced and retain the career path they always possesed, along with BMI doj for staff travel etc then there is no case to answer.
Anyone who is poised on the edge of the precipice awaiting to hear "job or no job" needs their head examined if they are then considering sueing the future employer for what is not there's to desire in the first place.