For all of you like me that want root without unlocking the nexus 10 after a 4.3 update, see Smiling Cat answer here:
1. Get Walrog Nexus Root Tool Kit
2. Get Chainfire's Supersu1.51.zip
3. Copy the zip to sdcard:
adb push supersu_path /mnt/sdcard/Supersu1.51.zip
4. Run toolkit, select your device (Nexus 10) and OS version (4.3) then boot using the default TWRP image the toolkit downloads automatically.
5. On TWRP recovery boot, press install and select the supersu zip.
6. Reboot then run supersu to confirm it's been updated.
The previous procedure does not require an unlocked bootloader nor does unlock it or wipe out data (unless you actually select that option).
Tested successfully on the first run.
I can confirm that this works!. I also used the default TWRP recovery, BUT, only as a temporary recovery.