Once Togusa got into the water, the first things he did were to test if his abilities still worked (they don't), and then the radio (it does!). This time, after the warning that this could be dangerous, he isn't leaving Koutarou's side. The harpoon gun and dive knife would not be his first choices of weapons, but it's all he can manage now.

But, the longer they're down here, the more competent Togusa seems to be getting, the more familiar with the equipment. Almost like he's remembering training that he had forgotten about.

As they approach the shrine, he chuckles through the radio. "Okay. Not what I was expecting."