Anyone who's had humans aboard their ships will know one thing for certain, even when asleep, humans can be very loud. They call the harsh, almost predatory growling-like noise, snoring. There was a reason if you want to allow humans to have quarters aboard your ship, you sound proof it. However, it's also often an indication of the human having an obstructed airway when they sleep, which could be, from a medical standpoint, worrisome. However, once you heard that sound, you knew they were well and deeply asleep. But then again, enemies also knew that sound meant they were asleep, too. What they didn't know, was how well humans can fake the noise and take someone off-guard. -- DaniAndShali
Science has attempted to figure out why Humans snore. Some theories say that the snarling growl would be enough to frighten predators from attacking their sleeping bodies. Some insist that it's merely a byproduct of evolution going with whatever worked well enough at the time. Whatever it is, it has become very important for a crew to know what their Human(s) sound like when sound asleep. Of course, there's always the 'light sleeper' who can go from unconscious to wide awake at the least provocation. In all cases, sound proofing is beneficial to the crew.
What's important about knowing the Human(s) normal noises is the simple fact that Humans know they snore. Some are even aware of the exact sound they make. Humans are also mimics. It's what has made them foremost in xenolinguistics in all of known space. All of these things can create a perfect storm, just like the events that occurred on the Miss Adventure.
Piracy, the Vorax, or both are common hazards in the outer space lanes. One of the many reasons why it's advisable to have at least one Human aboard. One or the other had happened to the Miss Adventure, the records were never clear and the combined efforts of witness testimony and forensics on the remains were unable to determine which forces were at work. Either way, they used a chemical sleep agent and literally dragged the crew to a holding area whilst they raided the ship.