What happened with water i though did be big flooding or something or what his plan?

Me thinks something extremely flammable was mixed in with the water

Lol I thought they were gonna electrocute them all haha

That water is a decoy, when they throw big ball (I'm not sure what they throw, it was big and round) to them it creates big splashes and disturbed their field of view so they wouldn't know where & when the next attack is. That, the man in last panel was send off flying by heavy ball, I believe they use canon on something to shot it.