How do I repair cracks in basement wall?

My problem: There is a vertical hairline crack in basement wall leaking about 3 inches up from floor. I found a wall repair kit online that I'm pretty sure I can use. But about 2 feet from top of wall, the crack disappears behind a wall and finished bathroom. Is it okay to fix the crack up to the point it goes behind the finished portion? Or do I need to tear down the wall and try to get behind the shower on the other side of the wall?