It means Miqobot found out herself in a position where she had no other option left than triggering her kill switch.
This means she will no longer operate until you close it and restart it.
It’s meant to protect you when something bad happens, for example, when stuck, instead of running into in a wall indefinitely and look suspicious, Miqobot shut down her link with the game and stop doing anything, it can happens when she lost track of where she were because of a bad grid, but it can also happen in other circumstances.