Okay -- a couple of new ideas materialized.
Pike tells Kirk "Your father was captain for 12 minutes and saved 800 people." Okay. I counted 22 shuttlecraft leaving the Kelvin in that one wide shot. Since they all seemed to be the same models and size (and the captain had already taken one to the Nerada, and one medical shuttle only had one passenger, two medicos, and a pilot), I have to wonder: HOW THE HELL DO YOU FIT 800 PEOPLE INTO 21 SHUTTLECRAFT?
They squeezed in? I know when my ships getting blown up and my life is on the line i'll happily press up against someone if it means getting to safety.
Also, it's possible there was another ship that was near by that was cut from the movie and the Narada didn't engage because of how badly it was damaged.