Blindside winger in a defensive lineout

I am an amateur winger and would like some advice on how to position myself effectively during a defensive lineout.

When the lineout is well up the field obviously the main responsibility is to be dropped far enough to be able to field a kick. But when it's in our 22 I'm always a bit unsure what my job is.

Here is a video from the Tigers v Saints game at the weekend:

https://youtu.be/lOBkbSztBVw?si=6ccnyuOdiogvCr1k&t=287

What is the 11 trying to achieve here? Is he trying to position himself so he can defend a maul or a forward coming through the middle of the lineout?

It seems to me like he should obviously be in the defensive line, but he hangs back behind the scrum-half, and Ben Youngs gestures seemingly to keep him there. So then when Freeman runs the hard angle he finds a big gap in the line and goes over for a try. I think the defenders were trying to account for something here but I'm not sure what.