Self defence, the mob was going to use the Struggle attack on the defendant, so the use of a "person defence weapon" in this situation is protected by the amendment, and its not my defendants fault that the rail company leaves switch levers unattended, and in the position that just so happened to destroy people on the track.
the protagonist will then use this incident to prove that public transportation is dangerous and proceed to bribe the local government into replacing it with a highway.