Comment 4 for bug 1083337

For what it's worth, I tried to reproduce the issue:

N7 status:
fastboot oem unlock performed
Stock Android image rooted

No further changes made at this stage.

I attempted to start the device via:
Power button + volume down button
Power button + volume up button
Power button + volume up & volume down buttons

None of these are successful in booting the device. Additionally, I appear to need to depress and hold the power button multiple times (or once for a very long time, I can't discern) before the device will eventually boot (into Android) again