"find some industrial buildings set for demolition"

Or some residential buildings?

"please resist discounting ideas based on practicality"

OK.

Imagine- Saint starts in the kitchen, Thor in an upstairs bedroom, Eruption in the living room. The first 2 minutes would be them fighting their way past beds and tv's and counter-tops and cupboards to get to each other! Then Thor might fall down the stairs. Could be very TopGear-carnage before the fight has even started. Gimmiky- maybe, but fun to watch