The walls are scorched. Smoke is thick in the air and debris litters the floor. The usually excited portraits are vacant and their canvas scorched. The occasional bang and pop rock the house, sending the light fixtures clanking above head and more dust to mix into the smoke. Bright flashes fly overhead and glass rains down.
A stream of people would be flooding down from above, and the room would already be insanely hot and smoky. It would be getting difficult to breath, or see the exit to the basement. Between the heat and the smoke, it is not possible to concentrate enough to apparate out. Flaming debris would be falling from above, and block the main exit. A huge flaming dragon would burst down the staircase behind those running, and begin attacking and lunging at those closest, the whole room now a complete conflaguration.