I've thought my PDC were firing on mines before, but that could have been a fluke--I don't remember if I was in combat or not. That could be a double-edged sword, though--since all PDC seem to fire at the same target, you probably wouldn't knock out those inbound torps.
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The Unpronounceable Krsqk
"Well, sir, at the moment my left processor doesn't know what my right is doing." -
Freefall