Yeah, I found out what happened. It all makes sense now.

Beadman could have ridden 3 horses, Shaft, Deferential or Forensics. When he was announced as the rider of Shaft, that horse suddenly came right in from $21 to $9!!! And when Quinn went onto Deferential, it suddenly went out from $9 to $15!!! Forensics even with Damien Oliver on, also went out from $6 to $9.

That just shows the huge impact that Beadman has on a horse's odds!!!