Finding Out
Some might say that this couple was reckless by snooping around on their own. They realized the chance of danger, but they were ultimately curious and had to know what they might find before anyone else got involved.
Soundproof Room
The water heater room was just a coverup. Whoever designed the trick room hoped to pass it off as normal to keep things hidden. As they opened the door, they saw soundproofing tarps on the ceiling, walls, and floors. They panicked, worried that criminal activities had gone on here.