Footsteps in the dark

So the other night, after the kids were in bed, J and I were watching tv when I thought I heard footsteps above us. We muted the tv and then paused it, but everything had gone quiet. It's not unknown for Rachel to wake up early and come up to us, but normally she would come down crying once she discovered we were not in bed. After a couple of minutes when there was still no sign of her, and J joking that we were probably being robbed, I decided I was imagining it and we carried on watching whatever it was we were watching.
When I went up to bed, however, I found that I was not as crazy as I thought, as there, tucked up snug in the middle of our super kingsize bed, with just her little head poking out, fast asleep was Rachel. She had obviously (although keep reading - maybe not) been for a wee as the bathroom light and extraction were on.
I asked her about it the next morning and she had no recollection of coming upstairs at all....

I didn't really think it was that noteworthy until tonight.
A similar thing occurred although first she went downstairs stood by the lounge for a minute seemingly crying before coming up to the loft. When she got to our room she made straight for the bathroom, as normal, but instead of going in she turned round and went back to the bedroom door, proceeded to pull down her pj's and I think she would have wee'd there had I not leapt out of bed and scooped her into the bathroom. When I did that she seemed all dazed and confused and jittery. But as soon as I lifted her off the loo and popped her into our bed she was fast asleep again!

I considered this to be strange (and amusing) until I had a vague recollection of being told that Auntie Sarah was a sleepwalker- I may be wrong about this - and it does run in families.
So my previous suspicions, that sometimes she comes up to our room as an automatic movement without consciously doing so, actually may have some foundation.
And it seems that we will need to make sure we lock the place up well at bedtime!
Although saying that, there is only one place she ever comes to in the night!