Well, most of the people who were acting as masters were probably tired from partying and doing things very late at night, while those they considered slaves were probably very tired from toiling from very early in the morning until late at night, so it's understandable that they were all still sleeping and didn't want to bother waking up and checking on things.
Of course, there might be people who weren't tired and had already woken up but still didn't want to bother with anything as long as it didn't involve any of them. Those so-called masters in the Sun Base were probably assured that they wouldn't be attacked by outsiders and just thought that their colleagues were making trouble.
As for those so-called slaves, even if they heard something or sensed something, they probably didn't want to get involved in trouble that would just make their lives harder, so they also didn't bother checking things out.
