Abby's CD player wouldn't slow down when the batteries got low it would just stop.
8 lemons cannot produce enough energy to power a portable radio.
Unlike retinal scans, iris scans do not read patterns of blood vessels in the eyes, but instead read unique patterns in the iris, the colored part of the eye that surrounds the pupil. Vasodilators would have no effect on the iris.
The getaway car is identified as a 1999 Chevrolet Impala. The car shown was a 1994 through 1996 Impala, as Chevrolet did not make an Impala for the 1997 through 1999 model years. A downsized version was introduced for the 2000 model year. It is also unlikely a 14+ year old car would have the original tires on it, negating the method used to identify it.
The iris patterns of two NSA operators were supposedly hardwired into every iris scanner by the manufacturer in order to provide a back door. For such a function, it would be unwise to rely on a live person as she might die at any time, rendering the back door useless. Especially if she's then made to lead the kind of Mrs Smith/James Bond double existence described by Duckie after the autopsy, where he found multiple past injuries, stab wounds etc. from all her covert missions. It would be much better to hardwire an optical pattern into the system that you could carry around printed on a plastic card or something.
When the power is restored at the end of the show the computer displays return to a fully operational state without going through a boot up sequence, revealing that the monitor signal had simply been reconnected.
About half-way through, a body is shown on the autopsy table while the power is out. She is dead and being autopsied, however you can see her breathing.
McGee finds a manual mimeograph machine. Since mimios haven't been in regular use since the 70s it's almost certain that the ink would have dried up long ago.
It strains credulity to believe the entire NCIS headquarters/Navy Yard didn't have a backup power system that could have pressed into service.