Output express form from block doesn't submit

Really stumped on this one. I've built a custom block. I'd like to give the user the option of choosing an Express form from a select box, and then render the form chosen when the page is viewed. I'm following this tutorial on how to render the Express form:


The trouble is, when the form is submitted, I get a 404 not found.

I'm assuming this is why:

<form enctype="multipart/form-data" class="form-stacked" method="post" action="<?php echo $view->action('submit')?>#form<?=$bID?>">

I do not have a "action_submit" method in my block's controller. I certainly could add one, but that would mean adding all the logic for an express form save operation. Also, these forms are variable and can change. I even tried making my block's controller extend the ExpressFormBlock controller. I got close there, but nothing submits. I'm not quite sure what do here. I would have been nice if the tutorial above shows you how to do this, or if it's even possible. What's the point of rendering an Express form programmatically? Any help or insight would be greatly appreciated. I've even attempted to load a stack programmatically that has the express form, but same issue. Adding a stack using the UI works, but this doesn't fit my use case.

Thanks in advance!