There is a huge difference between merely smashing a Holy Sword, that is what happened to the Sword of Faith, and unmaking a Holy Sword, which is what killing an innocent with it would do.
page 271 Grave Peril paper back
yea.... That's what I just said... Destroying the sword does not destroy the energy of the sword, just changes it.
Pure physical force can break the sword when it's vulnerable, still not the same as unmaking it. If the metaphysical event as the crucifixion gave the swords their significance, then a comparable event can change their nature.
The three swords are likely the three Watchers btw... The clue everyone seemed to miss from TC, is there is another supernatural restaurant in Egypt, same place esper was last active. One sword, one grace, one watcher based near where the sword was most active,
*Idk if you got the mortal philosopher reference, but you can't destroy energy, you can only change it, hence unmaking the sword is not simply destroying it.