This Doctor wasn't unique in the fact that she got a little bit lost from time to time- or just a little distracted. Losing track of time was pretty typical. It wasn't a big deal when you could go back nad make up for it, except without her TARDIS that wasn't exactly a possibility, was it? So stopping for the cup of tea then following a man about a dragon might not have been a prudent thing to do that the time.
And she was late. Not very late, but late enough to know she was late. Still, when she spotted River, the Doctor had to pause for a long moment to stare. There she was. River Song. A woman she hadn't seen in- how long had it been? Millenia? Or something like that. But not. The last time she remembered her she was an old Scot and it was just before the Library.
Oi. That was a night, wasn't it?
"River Song." She greeted her with a wide smile and stepped closer, freezing since she didn't know exactly how to greet her- a hug? Kiss on the cheek? Noogie? No, that wasn't right. Definitely not that one.