Nexus 10 won't boot after attempted unlock/root
Had similar problems. My Nexus 4 was discovered just fine, but Nexus 10 failed to be seen as an Android adb device. So I uninstalled the Nexus 4 drivers, rebooted, and then installed some unsigned drivers from internet called Naked Drivers.
After that both Nexus 4 and Nexus 10 were properly recognized.

Then, attempted to unlock the Nexus 10 using WugFresh NRT (I'm lazy, I know) and after a temporary install of twrp, WugFresh NRT told me to do a factory reset to prevent a bootloop. So I did this, but it told me that it failed a couple of times.
After reboot, found myself in a bootloop, exactly what I tried to avoid.

After some google search came around this movie that explains how to do a basic wipe, but from original recovery not twrp.

http://www.youtube.com/embed/T1Se7Hr9Cww

Written explanation of the steps from the video above (in case it goes down):


press and keep power, volume up and volume down to escape from
bootloop and reach the fastboot menu 
in the fastboot menu use volume up and volume down to navigate and select power off button to make a selection, so just select the recovery option 
you will reach the recovery mode (there is an icon with android robot on his back and a "!" sign) and press quickly all three keys at the same time (power, volume up and volume down). If you succeed, a blue menu will appear, so from there, just select your wipe option.


After I tried this, it worked and found myself at configuration screen for first time setup.

Next, I downloaded latest version 2.5 for twrp, replaced the old 2.4.1 in the folder WugFresh Development\data\Recovery_Custom\TWRP. After that, using the WugFresh interface I went for the root and also checked Custom Recovery.

This time everything went smooth and also twrp was upgraded.

Hope it helps.