A "Helping Hand" is no help at all

She rumaged in one of the medi-packs and produced a syringe.  "Here, this should help a bit. Should calm you down, although it could just as easily be a sedative...." And before he could protest she shoved the needle into his arm and injected the fluid.<END SNIP>
 
Dean and the gang watched as Amber unknowingly injected Dean's arm with sedative instead of Dante's.
Amber finished the syringe and stood up. Dante was still quivering and gibbering. "That's odd." she said, "should have worked by..."
<THUNK>
Her words were cut off as Dean's arm fell off, onto Dante. Dante screamed as the wet floppy limb landed on his face.
"AAARGHHH!" Now most people were screaming from the shock of it all.
Amber dove in and grabbed Dean's arm. She held it out to Dean, who grasped it with both hands.
 
Both hands.
 
Amber looked at Dean.
Dean looked at Amber.
"POLYMORPH!" they screamed and dropped the arm.
 
Onto Dante.
 
Again.
 
Dante let out a cry of utter terror as "Dean's arm" 's red and spurty end landed in his face, before it suddenly metamorphosed.
 
Into a gerbil.
"What?" cried Amber, in laughter almost. "Who's scared of gerbils?" she asked looking round, Dean leapt into her arms. "Hold me."
"You're scared of gerbils?" she asked
"Terrified, got mauled by one when I was a kid."
"How the smeg did you manage that?" asked Keats,
"Dean." asked Amber, "is that your worst fear?"
"No."
"What is?"
The polymorph transformed again.
"This."
 
Then the polymorph feasted on Dean's fear. After the meal, Dean fainted. And his body disassembled.
 
"Why." said Amber, "did we not try to beat it off?"
"I think we were all to afraid." said Tara
"Yeah." said Keats. "That was scary."
"Too true, I mean that was scary. I'd never have thought even a polymorph would have dared become a Frenchman's armpit."
"Wasn't it a Frenchwoman's armpit?"
"I dunno. Dean?"
"Yes?" Dean asked from the ground, somewhat groggily.
"Was it a female or male armpit?"
"It was a French one, thus it was unisex." he replied.
"Why hasn't your body reassembled?"
"I dunno, I don't think it can till I get the emotion back."
"Has anyone got a bag we can transport the rest of you in? We'll take it in turns to carry your head." asked Tara.
 
Dean "<THUNK>" Thomas