You can add a number of web controls into an accordion (found if you right-click in the accordion content area and hover over 'Insert Webcontrol'), such as the quotation control and the YouTube embed control. However, please consider the nature of the content before you add it in.
If you have a promotional video on the external website, you probably want to make it prominent on your page, rather than hiding it in a content cupboard. Whereas if you have a 'how to' video in the Intranet, visitors to the page can choose whether or not they need or want to watch it.