Closure Validation: Get $get doesn't resolve correctly

I've got a form where I need to validate that part of an input matches a date input. From the docs (https://filamentphp.com/docs/3.x/forms/validation#custom-rules) I should be able to resolve

Get $get

Get $get

in a function and then return my closure rule using it. However,

$get

$get

's value only contains the field I'm validating, not the entire form state.

Thus, any calls to

$get('value')

$get('value')

return null.

Screenshots attached showing the value of

$get

$get

and the code.