You might also want to monitor your memory and disk space as this is happening. Pi's don't always have a ton of memory or disk space available and I used to run into issues occasionally where MC would sometimes create memory pressure on the Pi which can lead to lock ups. If that's the issue, you can often ameliorate the issue by tweaking some settings (reducing thumbnailing priority, turning off memory playback, etc.).
I'd suggest setting up a terminal watching free -h and df -h just to get a sense of whether the lock up is something internal to MC or a resource problem.
