There are whirlpools in quickwater cave that lead to another section of the delve, one whirlpool lands the player on an invisible platform which they can drop down from safely, however the other whirlpool permanently traps the player.
There is a / command that you can type to fix this, I think it's /stuck but I'm not sure, type it in chat and hit return and it should rip you out of any location and send you to the nearest wayshrine, note that this will take a minute or two as it's a lot slower than normal fast travel
I know of the /stuck command Integral, thanks though.
Should have said myself it isn't technically permanent due to the /stuck command but it's not pleasant to have to use it. ^^
Especially in Cyrodiil since you'd have to run half-way across the map again depending on your faction.
There are whirlpools in quickwater cave that lead to another section of the delve, one whirlpool lands the player on an invisible platform which they can drop down from safely, however the other whirlpool permanently traps the player.