Getting a specific value out of array using get_attached_media

Don’t use the GUID. Despite appearances, that isn’t an URL. Use wp_get_attachment_image_src. Something like:

$image = wp_get_attachment_image_src($post_id,'full');
echo $image[0];

Or use wp_get_attachment_url with the post ID.

$image = wp_get_attachment_url($post_id);

Of course, I don’t know what the actual variable name is that holds your images but you should see the ID in the post objects and should be able to work that out. But, for example…

$media = get_attached_media(null,1);
foreach($media as $m) {
  var_dump(wp_get_attachment_url($m->ID));
}