[Heading over to the coat check means she can see that there's some amount of blood trail in between the spike zone and the eastern door to the Clockwork Atelier. Luckily, though, the coat check seems normal.

She can also see that the majority of the mess in the room is the south end she just came from.

--Homura have you considered that there are pack mules in the castle with you. Anyway, once she gets some nice mittens to wrangle the spikes, she'll find that trying to pull them up disturbs the entire snow cover around them for a considerable stretch. Also, where is she trying to grab spikes from, relative to the south wall?]