^ Scary yes, but is it a Phobia?
"a persistent, irrational fear of a specific object, activity, or situation that leads to a compelling desire to avoid it."
I can understand your fear being stuck in an elevator, but do you now have an irrational fear of them? Does it, for instance, make you nauseous to think about them? I mean any elevator, not the time you were stuck in one.
I empathise with being stuck in a train tunnel. Once when there was a fire at South Kensington station my train was stuck in the tunnel for 3 1/2 hours. It was the kids that kept us all going! But I'm not scared of trains.