A little off the top

"A guillotine!" said Miss Flava.  "I wasn't expecting that."
"What were you expecting?" asked Playfair, looking at her as though she were stupid.  "How you could have been expecting anything?"
"Oh leave it be, Playfair," said Miss Flava.  "You know what I meant."
"Sloppy speaking engenders slopping thinking," said Playfair.
"Oh, very Sapir-Whorf," muttered Miss Flava, making sure it wasn't loud enough for Playfair to catch.  "Let's go look at the guillotine then."
The guillotine was a spotlit blade mounted on two tall columns of wood with a thin bar stretched across the top of the two columns.  A rope stretched from the blade of the guillotine to a tying off point on the floor of the stage, around which it was wound in a figure-of-eight.  Beneath the blade was a black padded bench with a floral pillow a little after where the blade would fall.  A piece of shaped wood propped up against the bench looked as though it was intended to fit around the victim's neck, holding their head in place so that the blade could slice cleanly through without being blunted or turned by vertebrae.  On the floor next to the bench, behind it from where Playfair and Miss Flava had been stood in the wings, was a body.  Playfair saw it first, and sped up, while Miss Flava, seeing what her boss had spotted, stopped where she was and pulled her notebook out.
"Anyone we know?" she asked, holding her pen tightly over the pad.
"Not exactly," said Playfair, bent over the body.  "But I think we encountered his head just a little earlier."  He lifted up the chest of the body to reveal that it was headless.  The stump of the neck had little metal contact points and socket junctions instead of veins and bands of muscle.  Miss Flava put her pen away.
"He?" she asked.
"Very definitely male," said Playfair, looking further along the body, which was now clearly just a very lifelike mannequin.  "Either he's needed for some other part of the act, or the Great Stormy has some insecurities."
Miss Flava thought about that for a moment, and decided that she wouldn't like to have to guess.  "OK," she said. "So we have a guillotine on a stage, so it looks like we know what the rehearsal was going to be.  Head's in a cupboard, so perhaps it's not needed for the main trick?"
"We should probably ask Ronald and his dreadful sister," said Playfair. "They were supposed to be here helping with this rehearsal."
"Sister-in-law," said Miss Flava, patiently.  "Right, well, we can do that later unless you think this is important?"
"Everything is important," said Playfair.  "I've told you that, and I keep telling you that."
"Yes," said Miss Flava.  "But at the end it always turns out that some things were much more important than others, and what I really want to know if how to spot them."
"Start off by understanding that everything's important!"
"Shall we carry on looking around?"
They went off the stage the way they'd come, walking back through the prop-room in the corridor and through the sticking door.  They looked at the door that seemed to lead into the rest of the house; it was still locked.
"Do you think Ronald will have a key?"  Playfair was eyeing the door up.
"Possibly," said Miss Flava.  "Why don't you go and see if he's still here?"
"You go," said Playfair.  "You're better at negotiating than I am."
Miss Flava sighed and walked back out to the auditorium.  Calamity was still underneath the table, curled up now and making little doggy dreaming noises, the empty trays next her showing that she'd eaten all of the sandwiches.  Miss Flava shuddered a little, still worried that they might yet have a dead police dog on their hands.  She looked around, and realised that Ronald had managed to leave most of the stuff they'd thought he'd brought with him behind, taking apparently only his sister-in-law and their bags.  She went to the French doors to see if he was still in the carpark, but a thud back where she'd left Playfair had her running back to see what had happened.
Playfair was stood where she'd left him, but the locked door was now swinging open and the lock looked a little bent.
"It opened," said Playfair, smiling as though stunned.  "I was just standing here, and it... well, it opened."
Miss Flava didn't believe him for an instant, but gestured at the open door anyway.
"After you, Sir," she said.