If anyone else arrives here, which I doubt anyone will, you can kill all screen processes with: killall screen
I don't recommend this. You could end the mis service abruptly and cause a problem in the future.
What you should do is attach the screen session and shut down the mis server manually.
Use 'screen -ls' to figure out the name of the screen session, then 'screen
-R <session>' to attach. Then hit escape in mis to shut the servers down.
--- Mystic BBS v1.12 A44 2020/02/04 (Linux/64)
* Origin: monterey bbs (21:1/168)