You don’t see a way out of this; you’ll have to risk using your blowgun. That’s inconvenient, especially in the water. First thing to do is find a safe place to surface, so you swim around and raise your head under the nearest walkway.
Then you pull off your waterproof pouch, and get your blowgun and three darts out, keeping the strap around your wrist so you can keep hold of the thing. Next you’ve got to take your breather mask off so you can actually use it. The whole time, you’ve got to keep a firm grip on Bluesight, because you’re not sure if he can see properly yet.
Luckily, the officer is checking the water some distance away from you, and the younger knights aren’t far off from her. You doubt you’ll have much time to re-aim before one of them calls out for help.
You fire a dart at the officer, then quickly adjust and shoot the two younger knights. The officer lands in the water with a loud splash, but that shouldn’t raise immediate alarm at least.
Now your problem is that you don’t have time to get your mask back on or put your blowgun away. You’ll have to just swim with your head above water until you find better cover.
Before that, you give Bluesight’s hand a squeeze. He raises his other arm above water to sign that his eyes haven’t recovered yet. You squeeze again to acknowledge, and then move away carefully towards a patch of tall grass. Hopefully you won’t be spotted before you reach it…
“Marshguard in the water!”
Damnation. This really isn’t your night.
The alert’s already gone out, so another dart probably won’t do you much good. What else can you do?
Be a crocodile, just lunge for the alert-guy and hold them hostage.