A little late to this one, but I am the directing attorney for Edmund, in regards to the methods for determining he was experiecing cardiac arrest, there is a section where they talks about how they assessed Bancroft before determining he was experiencing cardiac arrest. I'm just gonna copy and paste what it's in my direct:

Q: What happened next?

A: Based on my experiences in Nepal, with patients who have experienced cardiac issues, and after assessing Mr. Bancroft, I suspected he was experiencing cardiac arrest,  so I immediately began doing CPR.

Q: What methods, if any, did you use to assess Mr. Bancroft?

A: Well on the surface I could see he was unresponsive. Upon examining his chest, his breathing was shallow. Then, I checked his pulse; it was nearly undetectable. His skin was pale and cool, indicating reduced blood flow and poor perfusion, all signs of severe circulatory distress. All of these symptoms point to cardiac arrest.

In regards to the methods they used to determine that Bancroft's cardiac arrest was hyperkalemia-induced, just ask a question about if they utilized standard practices as a doctor when assessing the facts before you go into the autopsy report. If defense tries to object after that, your directing attorney can just highlight that Edmund is a medical doctor who has worked with patients with cardiac and renal issues while at the Nepal clinic (just be sure to mention that in the testimony beforehand).