脊線

脊 = 兆 + 月 : Joan of Arc (ji) collapsed on the ridge (脊) of the moon during her hike in the space station's living room (Ø3). A vulture (兆) is waiting nearby for Joan to die so it can rip out her spine (脊).

线 = 戋 + 纟 : Mnemonic symbol: barbed wire.

线 = 戋 + 纟 : The silk worm wants to use the floating tank in the anthill's bathroom, but there's already Marie Curie inside—and she secured the tank by setting up barbed wire all around it.