Cannot hook plupload's JavaScript consistently

[tomdxw]

Visit /wp-admin/media-new.php and enter the following into the console:

window.uploader.bind('FileUploaded', function (){alert(1)})

Upload a file and once that's complete your function will be executed.

However if you visit /wp-admin/upload.php or /wp-admin/post-new.php and run that JavaScript you'll find that window.uploader is undefined.

I'm trying to prompt users to add additional information about the images they upload, but without access to the Uploader object that appears to be impossible.