"God showed mercy to Jonah by not letting him drown", but he caused the storm in the first place (or did not stop it, endangering all). Then he send him on a mission to preach the downfall, when gad must have known full well, that here would in the end no destruction. He made af ool out of Jonah, and the witnesses are like fools with their 1914, 1925, 1975 2075 predictions, ostensibly miraculously derived at by god's spirit-directed organisation.
In the end, blame Jonah, or ha-noj, because he got it all backward.