Could Linnet Ridgeway really have been asleep when Doyle shot her? It takes less than 2.5 minutes from the moment Linnet leaves the lounge to the moment when Doyle is left alone by the other guests (just after being "shot" by Jackie). Remember all of this happens in one continuous scene. According to Poirot's solution of the case, it takes another 30 to 45 seconds for Doyle to pick up the pistol, rush into his cabin and kill his sleeping wife. But could she have been asleep then already? From what we know, she only left the other passengers a mere 3 minutes ago and would have had to get to her cabin, take off all her jewels, change into her night-dress, prepare for bed, get into bed, and fall asleep in probably less than 180 seconds. [The theory doesn't require that she be asleep, only that she be in bed. She would have no reason to suspect her husband was going to kill her, so he could easily enter, walk up, shoot her, and leave.]

Filming stopped every day at noon because the heat reched temperatures of over 130 degrees F. [ You can see by the almost complete absence of shadows in some scenes (in particular, the Karnak Temple scene) that some scenes were shot at and around noon.]