I was able to save my P3S after a dunk in the lake 3 years ago.
The drone was submerged completely for about 10 seconds, at a depth of about 4 feet. The airframe completely filled with water through the air vents, and water was visible in the camera body.
I took out the battery before it even came out of the water.
On getting home I immediately took apart the camera and lens to let the moisture escape. I then took apart the white cladding around the body and hit it with compressed air in a few nooks and crannies around circuit boards and the like. I also air blasted the top of the battery pack. No need to worry about the motors much, but the ESC circuits are super vulnerable to water and shorting.
I left the naked drone (no white cladding) in the sun for a day or two, then indoors in a dehumidified room for a couple more.
After about a week I reassembled everything, and bob’s your uncle (ie., it worked).
Best of luck!