Free The Third Gate by Lincoln Child

exploring hits.”
    “Yes,” Rush said, glancing back at him. “You see, this was once the site of a prehistoric volcano. Even in Narmer’s day, the volcano was long gone. But traces of it remained behind in the form of subterranean lava pipes. Our belief is that the pharaoh selected a suitable lava tube for his tomb and had his workers expand and fortify it as necessary. Once it was sealed, the encroaching muck and water of the Sudd would do the rest. Anyway, when we first move to a new section of the Grid, the thing that must be done initially is to blast away the accretion of silty deposits from the swamp bed.”
    “That’s Big Bertha’s job,” Valentino said with a smile. He jerked one thumb over his shoulder, where—in the shadowy depths of the hangarlike space—Logan could make out a hulking machine that looked half Zamboni, half snowmobile.
    “Narmer thought his tomb would remain hidden away for all time,” Rush said. “But he could never have imagined the technology we’re bringing to bear—remote-sensing radar, scuba gear, global positioning devices.”
    “This is Romeo Foxtrot,” the harsh metallic voice intruded. “Thebubble mechanism’s acting a bit flaky. Status stands at forty-three percent.”
    The radioman looked over at Valentino, who nodded. “Depth?” he said into the radio.
    “Thirty-five feet.”
    “Keep a close watch,” said the radioman. “Abort if it drops below twenty-five percent.”
    “Roger that.”
    “Big Bertha does the scouring,” Rush resumed. “Then, the grid square is examined for hits—holes or tunnels in the swamp bed. If there aren’t any, the square is marked as explored and we move to the next square on the Grid. If tunnels are found, they’re flagged as Search for the next team of divers.”
    “Might find a sinkhole,” said Valentino. “Might find nothing. But we got to check each one. Sometimes the tunnels, they branch out. Then we have to map it—map it all.”
    Rush nodded at the monitor again. “And the results are recorded on that—and on the main cartographic display in the Operations Center—with archaeological precision.”
    “Found anything yet?”
    Rush shook his head.
    “And how much of the Grid have you explored so far?”
    “Forty-five percent,” Valentino replied. “By tonight, Madonna willing, fifty percent.”
    “That’s fast work,” Logan said. “I had assumed—”
    He was interrupted by a loud voice over the radio. “This is Echo Bravo. There’s a problem with my regulator.”
    “Check the purge valve,” the man at the radio said.
    “I did. Nothing.”
    Logan glanced quickly at Rush.
    “It’s probably nothing,” the doctor said. “As you can imagine, diving in these conditions is tough on equipment. In any case, the respirators are designed to fail open—even if one malfunctions it will keep delivering air.”
    “Echo Bravo to base,” came the voice. “I’m not getting air!”
    Immediately, Valentino walked over to the radio and took the handset himself. “This is Valentino. Use your backup second stage.”
    “I am! I am! I’m getting nothing. I think the dust cap is blocked!” Even over the radio, the panic in the man’s voice was evident.
    “Romeo Foxtrot,” Valentino said into the radio, “do you see Echo Bravo? His regulator’s malfunctioning and his octopus is apparently detached. You need to share air. Do you see him? Over!”
    “Romeo Foxtrot here,” came the other amplified voice. “No sign of him. I think he’s purging, heading topside—”
    “Oh, Christ,” said Rush. “Forsythe is panicking. Forgetting the rules.” He turned to the nurse. “Get a crash cart and an emergency team here—right now. And bring the water seal.”
    “What’s the problem?” Logan asked.
    “If he remembers his basic training, nothing. But if he panics, holds his breath as he surfaces …” Rush fell silent a moment. “For every thirty-three feet you descend, the air in your lungs loses half its