Jonathan Morris ) gurgled happily, sounding much like
they were saying :

The incident today just struck me as odd, even if there's a logical
explanation that I hadn't thought of (as there often is in these
cases). I just thought you keep the doors shut and open one as and when
necessary. It's not as if someone falling ill would, or could, suddenly
run off and take themselves to hospital. So, the doors opening makes no
difference to them. It certainly could make a difference in another
situation.

If the problem is somebody trapped in a door - and in this case, I think
the OP said that the doors had just been closed, so it's fairly likely - or
if somebody's having a panic attack or similar on a very crowded train,
then opening the doors would help.