zombie84 said:

They show a shot of him right before the DS explodes. In movie grammar, this is indicating that he is onboard the DS a second before it blows up. The film was not structured like that originally, but the editors decided to intercut Tarkin to increase the threat and remind the viewers why the DS is being attacked, and also give bigger emotional payoff when it drives home that the main villain in charge just got destroyed.

It was very much intentional, and that's all there is to it. "Stand by, stand by", shot of X-wings flying away, shot of Tarkin ONBOARD THE DEATH STAR, cut to massive explosion as all perish. They added that shot just to remind people--hey, Tarkin didn't evacuate, he is still onboard counting on the Death Star firing first, and they almost do but then BOOM.

End of story.

Unless U R willing to go for some crazy absurd fan-made conspiracy theory, he died. He must've been feeling a lot of pain and suffering from 3-rd third degree burns in that one crazy moment

However, some other user, I think it was Wexter, made a post about the EU expanded universe tarkin clone that died on the first death star (the DS1) and that tarkin was somewhere else at the time and that he actually survived the explosion!!!!!!!