MacOS has sometimes troubles with audio.

• Your playback stuck in a loop. 
• Your Mac was asleep, your playback does something crazy or wont play properly
• You have clicks and glitches
• Your interface stuck, after connecting it.
• or similar...

and more.

Command "KILLAUDIO" will "reset" all audio drivers, which are automatically restarted after some seconds.

It simply kills all drivers, MacOS brings them up again, automatically, no risk to use.