If it is a bugbear then don't hesitate to enquire here, the LIS situation is well known to the regulars, along with the added local habit of the LIS ground staff trying to close off the flight with indecent haste. As you now know, they also use the stairwell to back up the queue between buses, so timing is of the essence. FT is to make your life easier so ask away. My approach is to aim for the stragglers' bus, I know many FTers love to get to their luxury shorthaul seat ASAP but my motto is "last on, first off".