This is essentially the same problem as the previous one -- a fallen vent pipe, but with additional negative results. A vent was not properly fastened. It came loose and fell. The red circle at the top shows where it was connected.

The yellow square shows where the upper end was blowing hot fumes (note the blackened Sheetrock) against the wall. And the red circle at the bottom shows where the lower end connected. This is why intact Sheetrock on walls and ceilings is code -- as a fire barrier. There is fire risk here, as well as risk of fumes seeping into apartments.

And of course, it again shows why vent sections screwed together are the only way to go.