Bored to sleep?

I had been rocking a fussy Juliana for 20 minutes or so when I stepped into the kids closet to pick out their clothes for the day. I placed her on the floor in front of me so I could grab what I needed and pick her up again quickly before she became too upset. Except she became very quiet, studying the white walls, rubbermaid drawers and rack of clothing hanging above her (impressive, I know.) After roughly 2 minutes her eyelids began to droop and she promptly fell asleep. Not wanting to move her for risk of waking I let her stay there, konked out while the kids and I played in their room. Whatever it takes.