The safety on a Luger actually blocks the movement of the sear. On the guns with grip safeties (the "pedal" you mention) there is a mechanism that interlocks it's movement (the lever on the side of the receiver) blocking you from depressing the grip safety. When the interlock is moved to the fire position, you can press in the grip safety which will then move the sear block out of the way.
A properly tight and adjusted safety on the Luger should block the sear from moving out of the way of the firing pin (actually a "striker" design, similar to many modern guns) even if the gun is dropped. as long as the safety lever is blocking the movement of the grip safety.
If the safety lever is in the fire position, it could be possible for the grip safety to move under momentum when the gun hits the ground, and also possible for the sear to dislodge and allow movement of the firing pin. Both would be unlikely but possible.
Note that it's very possible to fire a disassembled Luger by manually pressing in the sear when the canon assembly is off of the frame. Always verify it's unloaded before disassembly.
Take your Walther PPS back to the dealer and request that they repair it's problem.
There is a writeup about the safety of the PPS here:
http://www.waltherforums.com/forum/f...ervations.html
Excessive dry firing can damage the plastic striker guide. Could this be the problem?
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