Hijikata will finally notice the tombstone is blank, and they're both very relieved! He'll check the entrance door to see if it's still locked... and assuming it is, they'll make their way down the creepy stairs.

Hijikata'll reload his Mayo-bazooka with it's final rocket for the day, and Mukuro'll keep to her trusty magic-bullet loaded pistol.

This has to be a trap but they've got nowhere else to go! (And besides, the cop can't ignore someone in trouble, and Mukuro can't ignore the danger.)