Speaking of Aether, passive scanners will pick it up very easily since it's that huge a signature. Typically, there's no hiding it when an aether system is active. However, in this circumstance, we can assume the station's aether system is hiding us with its much larger signature since we're in engineering. Once we move outside of the area however, anyone with a Mindy will have to shut down their aether tap and run off of capacitors/batteries until combat starts.
As for them hearing us through the floor, I just realized something. We can't hear crap right now, but engineering is still fully functional. Though it's dark and flooded with red emergency lighting and some light from the main energy system, everything is online and fully operational save for life support. The thrum of the aether tap and the faint light coming from it will also prevent them from 'hearing' us through surface conduction.
Sneaking is viable, so long as they're not doing an active scan. Outside of this area though, there's the extra hurdle of not touching anything.