I found it very interesting that Agatha Christie said that she thought that The Hollow would be so much better without the inclusion of Poirot. I myself found Poirot vital to the fact, and the fact that SPOILER the gun was found outside Poirot's home was an interesting twist a la Murder on the Orient Express.
For some unfathomable reason, I have always enjoyed Evil Under the Sun. Perhaps it is because of the relish I get when seeing characters contorted and misrepresented in adaptations, or the sheer satisfaction of a (not entirely conventional) ingenious plot, which makes Poirot question the most basic and obvious of assumptions.
Hey Soham, Since I assume you have finished reading the novel, perhaps I should put out a little spoiler to help explain. Do you remember how Dr Armstrong was an unwitting accomplice to Wargrave (Armstrong didn't know that Wargrave was the killer, and so tried to help him flush out the killer)? I would argue that it was Armstrong who somehow put the revolver in the drawer unnoticed (he was the last one up the stairs, remember, and could have easily slipped the revolver back in, unnoticed, since the men - Lombard and Blore - were more concerned about Miss Claythorne than the others, which we see when Blore and Lombard state they didn't notice where Wargrave had gotten to). I think that Wargrave slipped Armstrong the revolver from the food container while the two of them were behind on the stairs, and in the flurry of concern for Vera, the other two men rushed into the room, while Armstrong ran to Lombard's nearby room and slipped it in. If you'll notice, the first few dialogues spoken to Vera are by Lombard and Blore, and I think Lombard, with his affection and concern towards Vera, was hardly likely to wonder where the doctor was during this time, and Blore was so selfish he'd scarcely think about the other two. So why go through this rigmarole? I think Wargrave may have convinced Armstrong that doing so would lead to the discovery of the killer. He must have told Armstrong that if Lombard were the killer, Lombard was sure to be surprised that his revolver was gone and utter some sudden conjecture, or if the killer was Blore or Vera, he/she would cry out in surprise that the revolver was gone.
I agree with @ChristieFanForLife as we don't see Mrs Reynolds reacting strongly to these deaths - even Miranda, who was Joyce's best friend, displays little emotion. This, in my mind, shows two things:
Mrs Reynolds is more of a histrionic woman than one who directly displays emotion. We may also infer from Joyce and Leopold's irritating habit of sniffing out secrets, that she may not have minded greatly about their deaths, preferring instead to focus her energies on Ann.
That Miranda may not understand the full implications of death. We see from her friendship with Michael Garfield that he told her how wonderful death is, which may have made her feel that Joyce received more of an unjust reward than an early end.
Also, in respect to Mary Drower, I think that her great sadness and grief stemmed from the fact that Mrs Ascher was all the family she had left. Mrs Reynolds (at the point of Joyce's death) still had Ann and Leopold, and Miranda had her mother and Michael. I like to think, sometimes, that Mrs Reynolds may have been privately upset about the death, but chose to behave as normal in the interest of her children's upbringing.
I also found it very interesting that Rowena Drake was more upset (or appeared to be more upset) than either Joyce's best friend, mother, siblings or schoolteacher.
Which, in a sense, is the cruelty of life - not all deaths are lamented...