Yes, you could do it in the MR8. But why? You have N-track and it would be a lot easier to do it in the computer where you can see the section you want to mute or keep.
When you render all the parts that you want to keep down to one track it is seamless and will sound like it was done in one take. Cellard, the next time you do a vocal, record it three or four times. Then transfer the wave files to N-track and listen to each track making note of the best parts. Then use the cursor to mute the bad parts and then click the the scissors icon at the top left hand of the task bar. This will silence those parts. Once you have gotten rid of all the bad parts you can then render the good parts down to one track by clicking on the blue CD icon, also at the top left of the screen, and then choose mono track and press start. this will render the good parts to one wave file or track. I hope this makes sense.