Hello Carlos, and greetings from Brazil!

AFAIK, you can try the "undo" button. Not 
sure if that will work 

Outside map editor, you can also use cheat 
menu to kill all bots on the map.

And by last, I think you can select bots 
in a similar way as selecting floor tiles 
& obstacles work, but If I Remember 
Correctly, that didn't worked at first... 
Dah, too long without editing Maps ^^'

Any other question, fell free to ask!

Jesus Saves