Hi Pete,
A few things. If you had a cascade of debuggers it is very difficult to stop them. You need to stop the process that is generating them. There are a few ways to do that. To halt the current process press Alt + . (press and hold alt key then period)
This is highly likely to get your process but it may not. If it looks like your process you are good to go. You can try a few times and you might get lucky. (press proceed if it is not your process).
Since you are able to interact with the system on the World menu select: open > process browser. You can find your process and then right click on it and select debug.
Also your code is safe. It is in your changes file. From the World menu select: changes > recently logged changes ... and you will find your code. This works even if you kill your image (as long as you don't replace the changes file).
Hope that helps!
Ron Teitelbaum