Embedded Videos and Locked Navigation

Hello Heroes, 

I'm working on a medical course for clinical staff and have been asked to embed a YouTube video that is less than 3 minutes in the course. Further, they want to ensure the learner has watched the video before moving forward in the course, which is pretty common. My first challenge was getting the embed code to work properly with the requested start/stop point. I was able to fine tune that embed code from YouTube using Copilot and it works great in Storyline. 

Here's where I'm stuck. I embedded the video on a slide by itself. On the previous slide, I have a notice that coming up next is a video with audio, etc. Then, when they click "NEXT" it goes to the embedded video and starts playing. To prevent the learner from moving forward in the course until ensuring they have viewed the video, I thought I could disable the next button and set a trigger to go to the next slide when the timeline ends. However, because it's an embedded video, the timeline is 2-3 seconds, basically whatever I make it and it ends up advancing to the next slide before the video starts. 

I could adjust the timeline so that it runs for the 2:50 and have a layer pop up at the end with a button to move forward? What would you recommend me doing to accomplish this? The course includes another video that I'll have to configure as well, so I would really like to learn how to do this so that it works reliably with little complications. And yes, I have tested the embed code in our LMS and it starts/stops exactly where I want. Appreciate your insights and assistance learning how to make this happen.