Como no soy un asiduo usuario de este excelente utilitario de Linux, cada vez que tengo que trabajar con el tengo que ponerme a buscar cuales eran las combinaciones de teclas para operarlo. Mas aún, cuando lo abrimos en una ventana de consola y no podemos cerrarlo con el F10.

Acá van los atajos mas utilizados:

The 'F' (function) keys are widely used in mc for file operations. Read the bar at the bottom for their current function, which may differ according to the context, eg. browsing a directory, using the file viewer, or the editor. 
    In normal browsing mode:
F1 - help. More readable than the 2000-line man page, although difficult to browse.
F2 - user menu ( offers option to gzip files, etc.)
F3 - view (handy to check the contents of an rpm or tgz file, or read contents of files)
F4 - edit with internal editor, mcedit 
F5 - copy 
F6 - rename or move
F7 - create a directory
F8 - delete
F9 - pull-down - accesses the menu bar at the top.
F10 - quit. Closes mc, as well as mcedit and any unwanted open menu. 

If you don't have F keys, use Esc - number sequence (1-0) instead. 
F10 key in Gnome Terminal: opens the main terminal File menu instead, so click quit with mouse.