If you've never ridden on the DC Metro let me give you a little tip: the doors on the metro are not like elevator doors. In fact, there's even a pleasant woman's voice recorded and looped in the metro to let you know. If you try to race into a metro car as the doors are closing and your purse, child, hand, luggage, stroller etc gets caught on the OUTSIDE, while you are on the INSIDE - THE DOORS WILL NOT OPEN. That is exactly what the recorded lady's voice means: there is no sensor on the doors and once they are set to shut, they shut.
To warn you that the doors are about to close, they make a ding-ding-ding sound and a voice tells you "Please step back. Doors closing." Guess what happens then? Right.
Now, there is clearly some sort of sensor that signals a light or something to the - conductor? pilot? - person who operates the train to indicate that a door isn't fully closed. They open back up, the nice recording tells you again to "Please step back. Doors closing" and you have a moment of relief to gather your shit and get inside.
I have to assume that if your scarf, or purse strap, or maybe even the hand of your preshus child that you are carelessly dragging behind gets caught in the doors, it might not be large enough to signal that the door is ajar. I don't know for sure. That would suck, though. Also, HEED THE DINGING AND THE WARNING.
These are the things I've seen stuck on the outside, behind closed doors, while their owners, fretting, are on the inside:
-a large piece of wheeled luggage
-(almost) a BABY STROLLER
I don't think any of this is funny, necessarily, as I've also darted in at some point to avoid waiting 15 minutes for the next train. I also don't think it's funny when someone trips, or accidentally bumps a wall. Basically, I find no humor in other people being embarrassed. I've been embarrassed before, it's not a good feeling. But I do have to admit that I was a little bit amused this morning when the well coifed man with his Movado watch, Burberry umbrella, and impeccably tailored suit fretted and pulled, flushed and blushing while his wheeled briefcase sat on the platform behind the closed metro door.
The doors opened, of course, and he pulled his belongings inside, let out a big sigh and pulled his jacket down with force in order to regain his composure. He looked a little embarrassed, but mostly annoyed as though the metro was out to get him, personally.