Targeting Custom Checkout Fields for Conditional Checkout

I’m trying to set up a conditional checkout rule.

Example: When product x is in the cart, do not show checkout field x.

I have already added the appropriate code I need to do this. The problem is that I can’t get it to work because I can’t figure out how to target the custom checkout fields I created. Thus far, I can only get it to work with the default checkout fields.

For instance, to target “First Name” and make it disappear, part of the code I need to use is:

unset( $fields['billing']['billing_first_name] );

If I wanted to target other fields, I could also use ‘account’, ‘order’, and ‘shipping’ along with the appropriate selector for what I’m doing. This works just fine.

But how do I target the fields I created myself? As an example, here is the code for a custom field I added:

add_action( 'woocommerce_after_order_notes', 'call_script' );

function call_script( $checkout ) {

echo '<div id="call_script"><h2>' . __('') . '</h2>';

woocommerce_form_field  ( 'the_script', array(
    'type'    =>    'textarea',
    'class'   => array('extracheckoutinfo form-row-wide'),
    'label'   =>  __('What is the script?'),
    'placeholder'  =>   __('You can skin this section if you added the "script" extra to your purchase'),
    'required'    =>   true ),

$checkout->get_value ( 'the_script' ));

echo '</div>';

}

But if I try to use something like

unset( $fields['call_script']['the_script] );

in my code to apply conditional checkout rules, it does not work. So how do I target the custom field I created? I would really appreciate any help on this.