The Worthy
Ruby had been aware of all the moving players involved in the fight against Deathwing, and so of course she was aware of Thor and his hammer. Mostly in the periphery at the moment but as she landed (super hero land at that with the kneeling to upright), the mini-huntress blinked as she saw Thor land into a car and winced in sympathy.
That was when she noticed Mjolnir nearby. Not thinking anything of it, she switched Crescent Rose into it's resting mode and clipped it to her cartridge belt and then picked up the hammer and sped over to Thor as a bunch of rose petals (time was of the essence in a fight such as this after all).