Inserting rich text content into comment in Flow Designer

I have an Update Incident Record step in a Flow which handles a special incident type. The step updates a number of fields including Additional Comments.

The customer would like for us to do two things:

1. "@t mention" the caller in the comment.
2. Insert some rich text to highlight changes that may need to be performed by the Assignment group.

I would think this might be possible by scripting the Additional comments field assignment but haven't been able to make it work.

• Simply inserting @<First Name Last Name> doesn't result in an at mention.
• Wrapping the desired rich text in [code]<p><html markup goes here></p>[/code] doesn't either.

If this is possible, what am I missing? 

Thanks