If Shiryu sneak attack Mihawk, and Mihawk dies, then WSS was a fraud. Sneak attacks shouldn't work on the WSS, his name was originally named the Clairvoyant instead of Hawkeye...
Garp will rescue Koby with sengoku and tsuru help, but Garp is looking like he might die after saving Koby. This should motivate Koby to become the new hero of the Marines.