Remove array items from nested arrays

I try to remove a key / value from a $_GET string in case a given trigger string matches.

If the get was one level array that's simple to solve it, but because the $_GET can contains nested arrays, I have a litle problem.

Let's say I have the following $_GET string:

?nikos=vasilis&merianos=nikos&greece[corfu]=ionian%20islands&greece[corfu]=west%20greece&another_var[l1][l2][]=trigger-1&another_var[l1][l2][trigger-2]=value

that translated into the following by using print_r:

Array
(
    [nikos] => vasilis
    [merianos] => nikos
    [greece] => Array
        (
            [corfu] => west greece
        )

    [another_var] => Array
        (
            [l1] => Array
                (
                    [l2] => Array
                        (
                            [0] => trigger-1
                            [trigger-2] => value
                        )

                )

        )

)

In order to match the trigger string, that in my case is the trigger-1 and trigger-2 i use the following code:

$iterator  = new \RecursiveArrayIterator( $_GET );
$recursive = new \RecursiveIteratorIterator( $iterator, \RecursiveIteratorIterator::SELF_FIRST );
$triggers  = array(
    'trigger-1',
    'trigger-2'
);

foreach ( $recursive as $key => $value ) {
    if ( in_array( $key, $triggers ) || in_array( $value, $triggers ) ) {
        echo "I found it";
    }
}

What I need, is when the trigger matches to remove te given key from the current itterated array.

So, what is the best way to perform this action ?

- UPDATE 1 -

I just try this, but strill doesn't work:

$iterator->getInnerIterator()->offsetUnset( $key );

Any idea why ?