As this on the IFE system or your own tablet?

If it was on the IFE system you shouldn't feel bad at all for watching it and would be perfectly justified in continuing to watch. But, in the interest of defusing the situation, turning if off would be an option.

If it was on your own tablet, it is a bit different. While a grown woman should have no issue simply not looking at your screen, if the images are particulalry violent or sexual it is probably in bad taste to make those visible to others, given the tight quarters in a Y cabin.