I dont even want to guess if the flex goes into the crawl space. from that job they may just go into the living room wall, behind the tv so if they turn up the sound real load it will drown out a little air noise. wont short circut that much lol
At least the left a neat pile of rubble from the bricks removed to cram that flex through the wall. Considering the looks of the building, these were left to allow the neighbors to throw through windows and do other vanadalism.