rMBP temperature?

Could be, but are you on 10.8.3? Have you done the SMC update? If yes, do an SMC reset which might help. If not, update to 10.8.3 and do the update first.

 

Have you done an SMC reset?

 

It is normal for the CPU to be that hot during CPU intensive tasks, and depending of what FCP X does currently do (transcode or analyze in the background, or play back compressed footage) it is perfectly normal.

Those Macs in their heat - a sine of over-heating? - a short story by Mister GGJstudios

To learn more about Mac OS X: Helpful Information for Any Mac User by GGJstudios​

 

http://support.apple.com/kb/ht3964

 

The System Management Controller. You will not lose any data, or anything.

 

The System Management Controller (SMC) is responsible for many low-level functions on Intel-based Macs. These functions include:

Responding to presses of the power button
Responding to the display lid opening and closing on portable Macs
Battery management
Thermal management
The SMS (Sudden Motion Sensor)
Ambient light sensing
Keyboard backlighting
Status Indicator Light (SIL) management
Battery status indicator lights
Selecting an external (instead of internal) video source for some iMac displays