This one makes more sense if you read its prequel first.
The subway train screeched into another station. Someone disembarked a few cars up from the one Ben and Lisa sat in. Ben was knitting a sock on two circular needles. Lisa was adding a neckband to a sweater.
The chimes sounded, the doors closed, and the train lurched off again.
Ben knitted all the stitches off one circular so that the sock was suspended from only one of the needles, with the excess joining cord pulled out between two stitches at the halfway mark.
Another station, another few passengers left the train. Ben asked Lisa if she had the yarn clippers. Lisa said she thought Ben had them.
Behind them and across the subway car aisle, Wei Li and Chandra were giggling over something on a smart phone. As the doors closed, Chandra made a swiping motion over the screen. Both teenagers stopped giggling.
The train jerked back into motion and Olof slowly opened his eyes. The rest of his body hadn't moved and still looked like he was dozing — arms crossed, legs splayed in front of him.
Opposite him, Jennifer stared out the window, even though there was nothing to see but blackened concrete walls and utility wiring. She started as if something had caught her eye and leaned towards the window.
Ben rose from his seat as if getting ready to disembark at the next station. He wrapped one arm around the chrome support pole that ran between the top of his seat and the ceilling, hiding the circular needle in his free hand.
"So you found it?" said Lisa. Ben turned to her and nodded once.
Lisa rose and slammed her hand against the emergency stop strip above the windows. The train screamed to a halt, throwing Jennifer and Olof into the door partitions in front of them.
Lisa reached into her knitting bag and grabbed a smooth black ball. She threw it overhand onto the floor in the gap where the exit doors were. The ball broke apart on impact and released purple clouds of smoke. Olof, the two teenage girls, and Jennifer were all reduced to spasmadic coughing. Ben advanced towards Jennifer, his half-finished sock held over his nose and mouth by the excess joining cord of the needle left inside it. He looked like he was wearing a DIY version of the emergency oxygen masks used on airplanes.
Jennifer pushed herself back onto her seat and tried to stand, but a fit of coughing forced her to double over.
"Witch ninjas," she gasped. "I should have known from the kniting."
"Pretty slow for an eldritch demon, aren't you?" Ben took a gulp of sock-filtered air as he ducked around Jennifer, then took one end of the free circular needle in each hand and pulled it around Jennifer's throat, forcing her upright. He looked up at Lisa, who had pulled her knitting over her head so that her nose and mouth were covered.
"Now!" Ben shouted. Lisa leapt in front of Jennifer. She held a rune-carved dagger up to the coughing eldritch demon's eye, made sure she had the proper placement, then shoved the point of the dagger home.
Jennifer opened her mouth to scream, but nothing came out but the start of another cough. Her head started to collapse around the point of the blade, green mist escaping from her ears and nostrils. When there was nothing left but a smoking, blackened lump on top of her neck, Ben released his circular needle garrotte and let the demon's body fall to the floor.
"Impressive," said a voice beside them. Ben and Lisa whirled to face Olof, who had pulled his muffler over his nose and mouth and had risen to stand beside them. Wei Li and Chandra were still doubled over, coughing.
Ben pulled his own dagger out of his pocket and held it up to Olof's face. "You're not supposed to be in this dimension either, paladin."
"Yes," said Olof. "And those daggers pretty much useless against anything but demons. They're not even sharp. What else have you got?"
"You got anything, Lisa?" Ben glanced down and noticed the purple smoke was starting to dissipate.
Lisa shrugged, reached into her cargo pants pocket, and pulled out a steel knitting needle.
"Old school," said Ben.
"What are you going to do, scratch my back?" said Olof.
"No, this." Lisa kicked Olof in the groin. As he doubled over, she shoved his forehead back and pushed the knitting needle up one of his nostrils as far as it would go.
It was a classic stilletto kill. A thin trickle of blood ran out the nostril and down the length of the needle. Lisa shoved twice more to ensure the brain was pierced more than once.
"That's disgusting," said Chandra. She coughed, and a little bit of purple spittle appeared at the corner of her mouth. "But it doesn't matter."
"Why not?" said Ben.
"Because we put bombs under the subway car," said Wei Li. She held up the cell phone, which now displayed a countdown.
"Uh huh," said Lisa. "And how were you planning on leaving before the bombs went off?"
"Oh," said Chandra. "Right. Shit."
Ben glanced at the countdown display. Forty-three seconds to go, assuming these two paladin ninnies had made the countdown in seconds. He jimmied the door open with a needle gauge and slid under the train.
Chandra took half a step towards the opened door. Lisa held up the bloodied steel needle. "I could stiletto paladins all day."
"In seventeen seconds, we're all going to be dead anyhow," said Wei Li, flashing the cell phone display. "Thirteen. Nine seconds... five..."
The screen counted down to zero and flashed red. Nothing happened. The two teenagers stared at each other, then at Lisa.
"Amateurs," said Lisa, and flung crochet hook shivs at each girl. They stuck neatly into the centre of the forehead. Chandra's and Wei Li's bodies slumped to the ground.
"All done up here," said Lisa as Ben climbed back into the subway. "Were there even bombs underneath?"
Ben shrugged and pulled off his sock mask. "Yeah, but they forgot to attach the ignition wires to the explosives."
"Great," said Lisa. She pulled the unfinished sweater off her face and shoulders. "I should get this thing back on the needles. I want to wear it for real tomorrow."