The Springfield P9 in .45 is an early EAA Witness .45. The early Witness 9mm and .45s were voluntarily recalled due to a defective firing pin that would allow the firing pin safety to be installed in a position that rendered it invisibly inoperable, which is my guess as to what happened here. The other thing that would happen is that the firing pin would get stuck forward to varying degrees, leading to slamfires, runaways and (unsurprisingly) drop discharges.
Perhaps if the pistol was in the “cocked and locked” condition, the discharge wouldn’t have happened. For certain it wouldn’t happen if the chamber was empty.
Sorry for your misery. Get well soon.
And Springfield put their name on that?
But how did it fire if the hammer was not even cocked?
And saftey on at that!