Something like this happened to me, too
About a year ago, on full train riding home from work. I was sitting in the middle of the coach with earphones on, I notice something happening behind me, take earphones of and lean into corridor and look back. See woman laying flat on stomach at the other end of the coach, unconscious, 20 people right next to her ignoring/watching what just happened. I get up with other woman and run to her, asking bystanders (still sitting) what happened. They say, she came up the stairs and just collapsed. Woman shouting through coach for a medic/doctor, to our luck someone actually gets up and runs to us, being a medic. Medic tells me to hold up her feet while he checks her, other woman running to find conductor so we can get an ambulance at next stop.
Medic says she has some sort of shock and needs certain drugs, we can do nothing, so the two of us carry her (around 100 kg) to the next exit, still people just watching and not helping. Next stop we carry her onto the station platform, waiting for ambulance, conductor is there and stops train.
Luckily, the ambulance arrived just a few moments later, check her, and say it is nothing serious (she still being unconscious), she just needs some drugs and fast treatment. Medic and me get back into train, people who just watched everything are now taking photos of her laying on the platform. Medic asks them why no one helped, they say they didn't know what to do. Yeah, I didn't have a fucking clue what to do either, but at least I cared you dicks.
I was disgusted from what has happened there and felt miserable about this for a few days, cause not knowing if she got well again. Later realized, not everyone will help you, but the few people who will help, will care enough. Let's just hope there will always be a good person right next to you when you get into (medical) trouble.