How to force windows to respect the rmdir command in my button?

No need to use the DOS rmdir these days. You can get the same thing using internal commands, removing the need to use MS-DOS Batch mode and @runmode hide.

@set ChildPath={sourcepath$|noterm}
Copy MOVE * TO ..
Go ..
@keydown:none
Delete {$ChildPath} FAILNOTEMPTY NORECYCLE

You may find that works better.