RX100: Slow shutter speed without tripod - techniques and settings

Here's a shot I took in Herculaneum, the other town that, along with Pompeii, was caught in the Vesuvius eruption of AD 79. This is a mined tunnel through the volcanic rock over the largely unexcavated Palaestra. It's not the most interesting shot ever, but it's technically really difficult, as it was taken in near total darkness. It was so dark that I couldn't even see what the camera was focusing on. The first image is after some modest post-processing (no sharpening) while the second image is the OOC JPEG, shot using AMB mode.

After some slight post-processing

OOC JPEG, shot using Anti-Motion Blur mode. In real life the tunnel looked almost black.

I wonder which other pocket camera could have managed this shot?