-[X]Into the Depths
You and Shisui share a single glance. You could tell almost instantly that this building must have once been important. If only for it's resemblance to the Konoha Police building. Without even needing to verbally communicate Shisui takes the lead, and the two of you move into the building.
Almost immediately the path drops out from beneath Shisui, dunking him momentarily under the water before he regains his balance. Now drenched he quietly points out where the path dips before you get dunked as well, the water past this point reaching to chest height. From there the search of the building is slow going. Most rooms are empty, pieces of what could have been desks float, water-logged in the murky water. Pale light shines through holes in the roof, barely enough to see by.
And as you are about to give up, you tumble across a stairwell.
By again, the floor dropping out from under you. Floundering for a moment, you scramble backwards to higher ground, Shisui drawn by the noise wades through the water to where you are.
"What'd you find?" You spit out water that had gotten into your mouth from the dunk.
"I think its a stairwell. Couldn't see much but the steps were obvious."
As you check to make sure your floundering hadn't nocked any of your ninja tool loose, Shisui squeezes past, poking at the drop with a foot. "Definitely a stairwell. I can feel the steps. Considering how the water hides it, I don't think the flooding of this building was collateral from the fighting... Want to take a look?"
Status of tools confirmed you turn toward the stairwell...
[]Take a look. If Shisui is right, then something important might be down there.
[]Don't. You have no idea how long the stairwell is, and don't have a source of light on you.
[]Fallback and get advice from Kushina. She might be able to tell you if this building had anything worth hiding.