Seeing Barbara, it was on his list certainly. And he knew he needed to do it before the girl went to bed. Presumably she did sleep--students tended to have less flexibility in the early morning than billionaires.
But things came up and it was late when Batman arrived at his spot, surveying the Gordon residence. Things were quiet, no one keeping watch though he'd seen a patrol car pass by several times. However, when Batman saw that Barbara was nearly ready for sleep he hesitated. A long moment passed where he almost left, but he decided she would probably be more irritated if he didn't show up than if he caught her in her pajamas.
He was lucky the Gordon apartment was embedded in a maze of fire escapes and oddly angled buildings. It made his approach easy, he knew no one could spot him angling across the wall in the shade. Jamming a spike in between the bricks above her window, Batman held easily onto his rope and tapped on the glass. The window was now clouded with the swirling black of his cape, only the gleam of his lower face showing in the darkness.