Welcome and congrats on your shooter.
First you have a striker, not a hammer; that said you should not be able to set the striker to fire with the safety on. The sear bar has to be able to move out to allow the striker to catch on the sear bar.
The relieved safety allows the pistol to be unloaded with an already set(since we can't type c....ked)striker.
The fact that you can't hear the striker fall may be a function of dirty,gummy parts, weak spring, or poor hearing.
A good strip, clean, and lube is in order to start.