I suppose if your only exposure to IVs is film and movies, not realizing that it’s actually a long ass needle in a major artery is somewhat understandable.
Fucking hell, that must have hurt like crazy, though.
The needle doesn't actually stay in the vein (sticking arteries is done only rarely and for more specific applications, hence intravenous = IV), but you still have a length of plastic tubing that was inserted using the needle. So while there's nothing pointy inside you anymore, it's still more than enough to be very uncomfortable when janked out.
Definite
How old is the alien again..?