Goldy waves back before she finishes strapping Alanna up. "It's got to be tight," she explains, firming up the buckles even more.

She sees to her own harness next, then attaches carabiners to each end of two shorter lengths of rope. She clips one of them to Alanna's harness and one to her own.

"Now clip the other end onto the line and if you get tired or lose your grip, you won't fall," she says, sitting herself on the edge of the building, to one side of the rope that extends across.

"With any luck."