Mass actually does not come into play when we are talking about just falling objects. All objects fall at the same speed until they approach terminal velocity due to air resistance (which is why all objects fall the same in a vacuum). That value is the standard acceleration due to gravity and is around 9.8meters per second squared. So after 1 second, the object will be falling at exactly 9.8 meters per second. After two seconds it will be falling at 19.6m/s. Thats around 43mph. Obviously some objects will reach terminal velocity due to air resistance at MUCH lower speeds (such as parachutes) but for most solid objects you can disregard it for simple game physics.
Is it possible your lift is accelerating faster than that? At what point does the object detatch? This happens in real life as well which is why objects that are not secured on those fast dropping roller coasters just fly away from you. I remember as a kid all my friends would place loose change on their laps (in retrospect a stupid idea :).
The only way to make objects fall faster is to change the world gravity. Note that by default it is set to -980 which is in cm. If you convert it to meters you get the 9.8m/s ^2 figure I listed above which hopefully clarifies where that comes from.
I have experienced the feeling that objects are falling slowly in physics engines before (and seen the complaint many times) but I think a lot of it comes from the fact we don’t have much first hand experience seeing heavy falling objects other than in movies where they apply lots of FX like camera shakes that make everything more intense feeling. Or there are lots of shots showing mostly the relative vs absolute speed.