I wonder how many people say at each marathon “you’re going to die”. Even if this particular instance is true, I don’t see the warning as a story. In the legends associated with the Battle of Marathon, Pheidippides ran roughly 25-26 miles from Marathon to Athens after the battle, to announce the Greek victory, and died of exhaustion after delivering the message.
I can’t imagine anyone saying “you’re going to die”. To tell someone ‘if they participate in a race the next day, they will die” is very suspect, unless she’s crazy. That is not normal..at all.