I used great code* to make the pop-up video stop. Unfortunately it stops background video which played in the Hiro section too.
After a while I found this and solved it:
Tom thanks so much for taking the time to help others by posting this. The vimeo link you shared solved my problem instantly! I thought it was a webflow problem but it was just needing special embed code instructions so vimeo knows how to process 2 videos on the same page. I’m a happy guy