The topic title probably has the two worst words to hear on the subway. That happened to me today on the 
at 49th Street going downtown. The train was held until medical personnel arrived.
I don't know anything about the passenger's condition so my question deals solely with train operations. 49th Street isn't a good place to stop because it ties up local service behind the stopped train. Wouldn't it make more sense to take the train to 42nd street where passengers on the train could transfer to an express train to continue their journey? , 
and 
trains were sent down the express track at 57th street to Times Square to get around the train at 49th.