The RROD can be falsely given if your video cable is not connected or setup right, as well as if you don't have the power cord in right or have a power surge.
Your 360 is fine, it was just a false alarm due to the setting being switched accidentally.
It actually displays all 4 parts of the ring red if the visual cable is not configured or inserted properly. This is what the TC is probably getting confused with. The RROD is only 3 red quadrants of the ring.
To TC. Yeah your Sexbox is going to explode! All over your face...
Happened to me 2 times or so.