Dramatically unpleasant is an excellent description.
The blood-coughing isn't a guaranteed side-effect. The problem is that they can't really see that well where blood vessels and airways are on the available scans for such a procedure, and if the needle clips a blood vessel that's by an airway, the blood goes into the airway.
A little bit isn't that big a deal. When the words massive haemoptysis start becoming applicable it becomes a big deal.
In a weird way, I'm sure it will be a relief for everyone if pathology on the Thing, once removed, comes back as "yep that's cancer all right".