Hi. There's a catch about the bootloader mode (the menu you're describing). You have to press vol down to scroll down to Recovery, and then press vol up to select it. Pretty dumb IMO but that's how it is.
If you're completely sure you can't get to recovery using this method, you could try going into download mode and factory reset through fastboot:
Here's the guide to get fastboot working:
To go into download mode, shut down the phone completely, hold down the power button and volume down buttons. Then let go of the power button while still holding down the volume button and it should boot to fastboot (download) mode. The connect usb cable to your pc.
You can do a factory reset (format data and cache partitions) using fastboot -w.
Btw, is there any particular reason for going CM10? CM11 is just so much better now, nightlies are pretty good (12/20 has been rock solid for me, even with ART enabled).
Motorola Atrix HD Maxx [4.4.2][CM11 Nightlies]