I think you mean the "median nerve".
Speaking from experience with a past history of median nerve entrapment, it can be quite debilitating. Because it is my nature to downplay things (and my fear of a career ending surgical injury), I allowed my problem to progress to the point where the nerve conduction in my non-dom hand was significantly slowed, I had muscle wasting in my hand and constant pain at > 90 degrees unless I was "shaking the thermometer". I had trouble opening scrub brush packets and was impaired in some yoga poses. Almost as importantly, I couldn't open potato chip bags.
Fortunately, with surgery I have no residual weakness or sensory deficits and was able to be back in the OR after 10 days (
the surgery was absolutely painless; had it not been for the MFN sutures she put in, I honestly felt like I could have operated POD #1).
Hand injuries can be devastating. TV shows tend to overplay many things for dramatics but loss of median nerve function would likely affect the ability to grip a needle driver, forcep or other instruments, tie sutures or cut tissue. Sensory loss is meaningful as well in differentiating tissue planes manually, thickness, etc. So yes, a severe injury encompassing the entire hand could potentially be a career ending injury.