I’ve not been following it too closely but from what I know:
1. It’s an almost entirely circumstantial case - in many cases I think the causes of death are even in question so they’ll have to spend a lot of time copper fastening what evidence they do have, for each of the offences in turn. For example, it’s not enough that she was on shift on X night, but that there were no other people in a position to have committed the crime etc. There seems to have been quite a bit of fairly arid evidence about shift patterns, numbers of staff and the recitation of logs etc. as to what they were doing throughout their shifts etc.
2. A lot of the evidence relates to pretty long, granular medical testimony, all of which the prosecution has been put on full proof of. Days at a time talking through who administered mediations etc. The states of mind at the time.
3. They’ve found it hard to keep the jury together. I think they’ve gone through all of their reserves at this stage.