During the submission of no case to answer the prosecution attempted to use evidence from the defence expert, Dr Hall. This led to a rebuttal from Myers that reveals a critical detail: 

The defence DID attempt to call their witness but were blocked from doing so by prosecution objection.

(Note prosecution request relates to a misunderstanding, they thought the defence were saying air embolism isn’t a real condition and wanted to refer to Hall report which acknowledged it is real. )