We do not get to see John do canine CPR and we do not get to see John at the veterinarian. Instead we get to read about John telling Elly what happened. If John is a good guy, then everything he is saying is true. Let’s do a little fact-checking:
In order for a veterinarian to determine the cause of death, the pet owner would have to pursue a necropsy. It is unlikely John would get this answer about a heart failure so immediately. That casts some doubt as to whether John is relaying the information to Elly truthfully.
As mgl179 pointed out last Tuesday, John could have a reason for covering it up. He may be trying to avoid an accusation of child endangerment or the endangerment or abuse of an animal. If that’s the case, then maybe John is faking his visit to the vet and just telling Elly something that he could not possibly know that quickly. Elly wouldn’t know the difference.
That leaves Elizabeth, who helped John. Elizabeth was outside when April found the toy boat and she was outside when John came out. What was she doing outside where she did not notice April leaving the yard? I have my suspicions (Anthony), but all we really know is that she was outside. However, if she was involved in something nefarious, then perhaps she would be willing to help John cover it up.
Good Norse doggie!