A GFCI does not measure short to ground. It measures a difference
between current in on the hot and current out on the neutral. So, the
second the guy's drill "shorted out" the GFCI would have popped.

In fact, the code allows GFCI's to be installed in place of a 2-prong
ungrounded outlet. However, the receptacle must either be labeled as
ungrounded, or the grounding port must be permanently sealed. They
figure that a GFCI in that case is still better than the old 2-prong
outlet, or someone installing a normal 3-prong outlet.

I was watching CSI. It is a great show.

Some guy falls 12 floors. His drill has been shorted and the ground
plug has been cut.

CSI says the GFCI is useless without the ground plug. false