Hello!
Well, if my comment helps anyone.
See, it is possible to have an application with the index in webroot, according to the documentation.
In the documentation it is also exemplified as redirecting to another path outside of the webroot, if you so wish.
"If your site is not at the webroot level you will have to uncomment the RewriteBase statement and adjust the path to your directory, relative from the webroot."
So for those who still have questions, you can find out at: link
I'll leave here a setting that might help:
An example for an app with the files in the '\ web' folder and the Silex core in webroot '\':
/public_html/.htaccess:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^$ /web/ [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !^/web/
RewriteRule ^(.*)$ /web/$1
RewriteCond %{SCRIPT_FILENAME} -d
RewriteRule ^website.com/(.*[^/])$ http://www.website.com/$1/ [R=301]
</IfModule>
/public_html/web:
<IfModule mod_rewrite.c>
Options -MultiViews
RewriteEngine On
#RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [QSA,L]
</IfModule>