We didn't necessarily see the Second Doctor's regeneration, and the first time we saw the Third, he came out of the TARDIS. So he could have regenerated there. The Third regenerated just a few meters away from the TARDIS. The Fourth and Seventh were within a few kilometers of it. (Perhaps the Seventh's distance from the TARDIS when he "died" was the reason his regeneration into the Eighth was so delayed.) We don't yet know how the Eighth (or the "Hurt Doctor") regenerated, nor do we know how or where it will happen for the Eleventh.