After executing a shell script in Keyboard maestro, not "feedbakc"

I create a hotkey only for Firefox as

Which is "working" so far,

except that, I would like to see the "error" of this script. It is not showing in anywhere even the error option is chosen as below as I try the hotkey. As also shown below that "Profile In Use" Popup/warning/error after choosing one that is indeed used.

basically, would like apple(the os) focus on the "Firefox-choose User Profile" window, so user can use keyboard to navigate up/down to choose a profile to run. then if the os detect that Profile In Use, os just bring up its windows.
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summary: It that possible for us to write a script that easily firing up /switching between Firefox Profiles instance. Just like Chrome it has a feature that switching Users using keyboard shortcut.

The action will display any output (to stdout or stderr) from the script.

To see what would be displayed, run the same command in the Terminal and see what is output.

Note that this is output from the script, nothing that the UI does will be reported (unless the script actually outputs something related to it).

Also, Keyboard Maestro is complaining about something, see the warning triangle in the bottom right corner of the editor window. You should resolve that (click on it to find out what is wrong).