my $inAbort;

##</code><code>##

sub abort_routine {
    return if $inAbort;
    
    $inAbort = 1;
    
    debug("+abort_routine");
    debug("abort_routine Array_Index: $Array_Index");

    # DO SOMETHING USEFUL HERE TO CLEAN UP THE PROCESS

    $MW->destroy();
    debug("-abort_routine");
}

##</code><code>##

...

        $button = $MW->Button(
            -text    => "Shutdown and close",
            -command => [ \&do_close ] )->pack( -side => 'bottom' );

...

sub abort_routine {
    debug("+abort_routine");
    debug("abort_routine Array_Index: $Array_Index");

    # DO SOMETHING USEFUL HERE TO CLEAN UP THE PROCESS

    debug("-abort_routine");
}


sub do_close {
    $MW->destroy();
}