Busca recursiva e remover em array?

Eu estou trabalhando com um array multidimensional eu quero ser capaz de remover uma matriz (e todos os filhos) que correspondem a um id.

A função que tentei é:

function removeKey($key, $array, $childKey = 'children'){
    if(isset($array[$key])){
        unset($array[$key]);
        return $array;
    }

    foreach($array as &$item)
        if(isset($item[$childKey]))
            $item = removeKey($key, $item[$childKey], $childKey);

    return $array;
}

Meu array de exemplo é:

Array
(
    [5] => Array
        (
            [id] => 5
            [parent_id] => 
            [menu_title] => Drinks
            [page_title] => Drinks
            [status] => 1
            [products] => 0
        )

    [1] => Array
        (
            [id] => 1
            [parent_id] => 
            [menu_title] => Electronics
            [page_title] => Electronics
            [status] => 1
            [products] => 0
            [children] => Array
                (
                    [2] => Array
                        (
                            [id] => 2
                            [parent_id] => 1
                            [menu_title] => Computers
                            [page_title] => Computers
                            [status] => 1
                            [products] => 0
                            [children] => Array
                                (
                                    [4] => Array
                                        (
                                            [id] => 4
                                            [parent_id] => 2
                                            [menu_title] => Apple
                                            [page_title] => Apple - Imacs and Macbooks
                                            [status] => 1
                                            [products] => 0
                                        )

                                )

                        )

                    [3] => Array
                        (
                            [id] => 3
                            [parent_id] => 1
                            [menu_title] => Mobile Phones
                            [page_title] => Mobile Phones
                            [status] => 1
                            [products] => 0
                        )

                )

        )

)

e o resultado que estou procurando (chamando a função com(2, $array, 'children')) é:

Array
(
    [5] => Array
        (
            [id] => 5
            [parent_id] => 
            [menu_title] => Drinks
            [page_title] => Drinks
            [status] => 1
            [products] => 0
        )

    [1] => Array
        (
            [id] => 1
            [parent_id] => 
            [menu_title] => Electronics
            [page_title] => Electronics
            [status] => 1
            [products] => 0
            [children] => Array
                (

                    [3] => Array
                        (
                            [id] => 3
                            [parent_id] => 1
                            [menu_title] => Mobile Phones
                            [page_title] => Mobile Phones
                            [status] => 1
                            [products] => 0
                        )

                )

        )

)

mas o resultado que estou recebendo é

Array
(
    [5] => Array
        (
            [id] => 5
            [parent_id] => 
            [menu_title] => Drinks
            [page_title] => Drinks
            [status] => 1
            [products] => 0
        )

    [1] => Array
        (
            [3] => Array
                (
                    [id] => 3
                    [parent_id] => 1
                    [menu_title] => Mobile Phones
                    [page_title] => Mobile Phones
                    [status] => 1
                    [products] => 0
                )

        )

)

Eu não tenho ideia do que está acontecendo aqui!

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