It would be fitting and extremely hilarious. Then it would be sad and heart breaking that both group of people exist in this world and wish to shed the bloods of innocent human beings.
Swiss guards would probably handle it, possibly after the damage has already been inflicted, and then most likely the current pope would issue a statement about mourning for the lost and the need for peace and love and other inclusive statements reaching out to the global Muslim community, while also criticizing the existence of fundamentalism and religious deviance, as he has done with the recent Paris attack and other acts by Islamists.
Swiss guards would probably handle it, possibly after the damage has already been inflicted, and then most likely the current pope would issue a statement about mourning for the lost and the need for peace and love and other inclusive statements reaching out to the global Muslim community, while also criticizing the existence of fundamentalism and religious deviance, as he has done with the recent Paris attack and other acts by Islamists.