When you play as kai you can use here arrow gun, but she can't fight so that make her weak. But it's funny when you shoot arrows at people more then once

I was stuck on this part for 3 days and could figure out what the guide meant by using the sqaure button to guide the arrows to hit the soldiers. Everytime I would do it, I couldn't guide the arrows. In the options screen you have to turn off the aftertouch. Once you turn it off, you will be able to guide the arrows. This will give you time to shoot each soldier that come shen's way.