Sina should have known better, and perhaps she did, but didn't care; either way, the knife sinks easily all the way through her right hand and into the ground, resulting in an anguished scream from the smallest elf.
Her first instinct is to tug away, but of course that isn't going to work, so she tries to stay still instead, willing magic toward the wound-- magic which is abruptly gone again, causing her to sob once or twice, a helpless, juvenile sound.

And then from her shard comes a pop of energy. As Sina's body gives a small jerk from the force of it, her breath leaves her, both from the pain and the shard's proximity to her lungs. Eyes streaming and voice briefly silenced while she tries to take a deep breath, she seems to actually forget about their tormentors long enough to take a long and uneasy look at the deceptively peaceful sky.