"Digging Your Own Grave"? Please. If you ask me, Shinki probably had Byakuren's grave dug centuries ago. She's just been waiting for a good enough reason to boot her Buddhist ass into the coffin and bury her alive.
Besides, doesn't Shinki's smile in the top-right look a bit odd to anyone? Not so much 'poorly-drawn' odd, but 'unsettling' odd?