I don't usually work frontline, but I was given brief training on accessibility and dealing with incidents, and similar to what District has said we are told to always offer assistance no matter what has happened - usually, in the case of someone incapacitated we'd phone police and then they'd deal with the situation, either requesting an Ambulance or waiting around with staff. I've never dealt with a passenger having a panic attack, or similar, but had one who threw up and then fainted on a train due to heat. We got them off the train and into our little back office, were we gave them some water. We asked if they wanted paramedics to come check them over and they refused. However, we still didn't feel like letting them go back off on their own so called for a taxi. The lady was on her way to work at the time so we also called the employer to let them know she wouldn't be going into work today. Taxi turned up about 25 minutes later and we left her with the advice that if it happens again, to call 999.
So whilst we have no specific training to the act you mention, most of us can use common sense and if you requested an ambulance, you would get an ambulance. As with any workplace you may get the odd one who'll be more hesitant too though so even if a TOC does have a policy like that you'll still likely find some who'll act in a similar way to the staff you've mentioned.
As you've already done, contacting the TOC is definitely the best way forward