“OK, it goes all the way through, but it’s a tight squeeze. Alex and especially you, Tank, are going to have to hold your breath in some places. Everyone try not to touch anything on the way through. This fall probably occurred hundreds of thousands of years ago and is not likely to move. However, there is still a chance that the rocks that have already fallen are poised dangerously one on top of each other. An inch or two can make all the difference. Our slide through the choke hole could undermine the supports of the whole pile, and cause it to suddenly collapse into a new shape, which may be far too small for us to squeeze through. Or worse, it could collapse into a solid compressed mass—and we really don’t want to be under there if that happens.”

Monica checked everyone’s cave suit for unnecessary items or bulges. “OK, we need to stay close together so we can actually see each other’s feet. Take off your packs and push them ahead of you. Take it slow and don’t panic. If you get a little caught up just breathe slowly and unhook yourself. There will be people in front of you and behind you to help. One more thing: avoid my red markings. I’ll go first.”

Aimee slithered out of her backpack, and holding it in front of herself folded her arms around it. The size was comforting and also meant no one saw that her hands were shaking. She closed her eyes and silently mouthed to herself, if Monica can do it, I can; if Monica can do it, I can. She really wanted to be home now.

She jumped when Matt bumped her elbow as he stepped forward, intending to go into the hole next. Alex overruled him. “Sorry, Matt, Takeda goes next to give us all some cover on the other side. Tank, you go last. Can’t have you corking us all up now, can we?”

Tank laughed. “Don’t mind none; I reckon you’ll have wiped it all clean by the time it’s my turn.”

Aimee looked at Tank’s bulk and hoped his good humour was matched by luck. She hugged her pack and waited for her turn.