QUOTE(andante_in_c @ Mar 23 2012, 07:57 AM)
Make sure to tell the steward that you have an appointment afterwards if they are running late, as sometimes they can be flexible with tea breaks etc.
The first thing is to say don't panic - either way, there's nothing you can do at this point in time, so save your energy
As andante_in_c says, here the steward is your friend! When you arrive ask the steward "are we running to time?" If the steward says yes, then you can smile and say "oh wonderful, I have a hospital appointment afterwards, so I shouldn't be late for it".
If the steward says "no we're X minutes behind time", still don't panic
Firstly listen, because if they say '3 minutes late' you likely have nothing to worry about
But, if it seems it might be a problematic running late, this is where you can say "oh dear, I have an appointment at X-place at Y-time, do you think I'll make it?" At this point the steward will doubtless do helpful stewardly things about the flexibility where possible.
I think it is important to say it is a hospital appointment, because then you can get together and roll your eyes at how these things always happen on the same day at the same time, and how hard it is to get hospital appointments anyway, and would you believe how long it takes to see my GP these days, and so on (none of which may be true, but there's nothing like a bit of bonding to get people more inclined to help you out!! Hopefully you won't have a young steward who's never had a days illness!!)