If you want to protect embedded content on a Post/Page, you can wrap the embed code in an s2Member shortcode conditional (see WordPress Dashboard s2Member API / Scripting Simple/Shortcode Conditionals) to prevent the embed code from showing for users who don't have the necessary access.

The following example only allows users with Level 1 access or higher to see the embedded YouTube video:

[s2If current_user_is(s2member_level1)]
    <iframe width="420" height="315" src="https://www.youtube.com/embed/qlKn-I-0W6U" frameborder="0" allowfullscreen></iframe>