Potassium benzoate?

Matthias turned the corner slowly, humming the theme to Mission Impossible, back pressed up against the cold dungeon wall. Dun, dun, dun. DUHDUHDUH dun dun, dun dun DUN DUN DUN. DUHDUHDUH-
Two guards sitting in front of the heavy wooden door. They weren't particularly attentive; one was asleep., the other on his way there. Matthias turned back around and walked over to Farrago, smiling. "And now... we WAIT."
And wait they did. Not long, though, ten minutes, fifteen tops. Farrago sat, jibbering nonsensically to her bear, which, Matthias found by listening to her, was named Merlin.
"Alrighty. I think they're both asleep now... stay here."
Silently (or as silently as one can be in huge, studded, chained-up boots), he walked past the sleeping guards, pushed the door open just wide enough for him to slip through, and did so.
His eyes watered at the pure, amazing beauty of the room. It was truly a paradise. Weapons lined the walls and the roof. Piles of swords, maces, and various other generally unpleasant objects reached from the floor to the weapon-laden roof. He dropped to his knees, awestruck by the pure amazing...ness of the room.
"Farrago!" he half-whispered, trying to get the sound across the hall without waking up the guards. "Farrago, commere! Be really quiet, though-"
"Hrm?" a guard woke with a start, then turned and looked at Matthias. The cyborg was positioned half-hanging out the door, and swung his steel arm backward, cracking the man square in the face. He slumped to the floor, not going to wake up again any time soon.
"Farr, QUICK!"
The girl snuck across the hall and into the room.
"Look at this. Look at it all. It's beautiful."
She gazed around, not quite as smitten as Matthias had been.
"Here," he said, handing her a bow of pure silver he picked off the wall. "Take this. Look for arrows." He turned and began digging through piles, sliding daggers and shurikens into his trenchcoat pockets.
Farrago sank to the floor, talking to Merlin. She was well into the middle of a conversation when she was suddenly cut off by a scream of "YES!"
She turned to look at Matthias. He stood, holding a shining, almost crystallic blue blade above his head. "I HAVE THE POWERRRRRRRR!"
He sheathed it across his back, then grabbed a crossbow and slipped it into his coat. "Well, let's go."