Instead of having a button "Volver" when the videos are played, it could be really god to have a bar at the side that has the same index that is showed when you click on "Volver", so you can see what is the index of videos without stopping the current reproduction, and of course, inside that index that you could go to a prior level (Take an example of what I mean in, for example, looking in an app like Okular, that you can have a side bar with the index and you could hide or show it).
Instead of having a button "Volver" when the videos are played, it could be really god to have a bar at the side that has the same index that is showed when you click on "Volver", so you can see what is the index of videos without stopping the current reproduction, and of course, inside that index that you could go to a prior level (Take an example of what I mean in, for example, looking in an app like Okular, that you can have a side bar with the index and you could hide or show it).