From the "Something You Don't See Everyday" Department

So as we are landing at Heathrow, the pilot tells everyone to stay in their seats for a "mechanical problem".  We pull up to the gate, and the door opens and 3 police board the plane and pull one guy sitting 2 rows from us off the plane.  Then all of our passports are checked just as we get on the jetway.  Mechanical problem, indeed....