Comment by grogenaut

For context a GCS Score of 3 is:

+1 Your eyes don’t open for any reason. +1 You can't speak or make sounds. +1 You don’t move in response to pressure.

So you get points for existing, and the tests can include causing pain (pinch ear, press nail bed, knuckles to chest [depending on jurisdiction]) to make someone have movement.

However, while GCS of 3 is the bottom of the GCS chart, it's not the only measurement used.

"Conclusions. We believe that patients with blunt head injury presenting with a GCS score of 3 should be treated aggressively. Our results showed that 50.8% of these patients survived their injury and 13.2% achieved a good functional outcome at the 6-month follow-up." - NIH

My favorite part of GCS: Emergency care books say "don't worry you don't have to memorize this, you'll always have a chart", yet calculating it exactly is on 2 different US emergency care national exams.