Mr Silver wrote:
^ But there was no pressure release nor did David show signs of any resistance when opening it. This suggests one of two things, either Spock had an in-built release switch (which would be stupid, since he was dead) which broke the airtight seal, or the Casket wasn't sealed at all.
First of all, we don't know exactly what kind of mechanism it had. Perhaps the casket is self-opening to a degree, like how the door of your microwave opens a little when you press the button.
And given that we've seen Key'lehr travelling in a similar way (albeit with a life support system), I'd say it's possible that there is indeed a release catch inside the thing, if only for safety's sake.
If it wasn't air-sealed, then it's quite frankly impossible that Spock's corpse would have managed to make the trip to Genesis (and creating a massive plot hole in the process), given the effects of the vacuum of space on organic matter (the force would surely pull Spock's corpse from inside the coffin, if not crush the casket into a ball!), not to mention what happens with an atmospheric entry. The casket would have been made out of duranium, presumably, but even that would be useless unless it was properly sealed - as all space ships are.
Why would the casket crush if it wasn't air sealed? If it wasn't air tight, then the air inside could be sucked out into space and then the pressure would be the same and the casket wouldn't crush. And Spock certainly wouldn't have been pulled out through a little hole a la alien newborn in Alien Resurrection.
And David clarified that the gravitational fields were in flux and it could have soft landed. And even if the landing did damage Spock's body, the Genesis effect would have restored him.