Seeing how the others were already trying to figure out what to do next, Runo turned his attention back to the water spout and filled the container he had brought over. Once it was filled, he attempted to turn off the water flow the same way he had seen it turned on, but only managed to get it to a tiny trickle rather than shutting it all the way off. With that solved, he took the water container out of the way of the others and attempted to wash his shoulder.
It wasn't all that easy, since all he could really do was splash water onto his shoulder with his hand, but it was getting something done, at least. The cold water felt really good, too. Although, exactly how he'd wrap the wound after, he realized he still hadn't figured out yet. stopping for a moment, he stared at the water as he thought about how he probably should have done something about that first.
...Or maybe...
After a moment more of thought, the merman began scooping up more of the water and placing it in his mouth this time. He wouldn't need bandages if this worked. After swishing the water around in his mouth for about a minute, he turned his head and spit it over his shoulder to the area he couldn't reach before. He flinched slightly at first at the weird feeling, but soon noticed the pain dull slightly. It worked! Scooping up more of the water into his mouth, he repeated the process a few more times, feeling the pain slowly ebb out of his arm as he did so.