"I'll do it." said Tom, "Do I need some code to get in?"
"The main entrance is from the bottom. Sort of like if you held an empty glass upside down underwater." replied Sgt. Sweet.
"Alright, no point standing around any more" said Tom, and he attached the holster with the gun to his belt. He put the breathing mask over his mouth, and jumped into the water.
He followed the cable the bouy was attached to, deeper and deeper into the water.
As the natural light from above decreased, eventually Tom saw the artificial lights of the lab below. "At least the electricity is still on." he thought.
As he approached the base, he saw there was a larger central module and a few smaller modules connected with tunnels. He decided to look under the central module for the opening.
And he found a ladder at the bottom, leading up into the base as described. There was a small submersible craft floating in the pool. Tom climbed up the ladder, as stealthily as he could, his head swiveling around, and his hand over his gun.
He didn't see anyone. He stood up on the floor, and took off his breathing mask. Looking around, the obvious exit besides the pool in the floor, was a closed metal door. He also saw piles of scuba tanks, wetsuits and drysuits hanging up on racks, lots of tools, and other stuff he didn't recognize.
"Well, I got this far, might as well try the door now." Tom took the gun out of its holster, tilted it to drain as much water as possible, and put his other hand on the handle of the door. "Can I really do this? Is there anything I'm not thinking of?"