How did Tony Stark remain alive after Thanos impaled him with his own iron suit, in Avengers: Infinity War?

As we have seen an angry irritated Thanos impaled Tony with his own suit and then preparing to go for final blow. Surprisingly, at that very moment, Dr. Strange agreed to give up the ‘Time Stone’ and Thanos in exchange spared Tony’s life. Now there are three possibilities why Tony survived even after getting impaled by Mad Titan —

  1. Thanos did impaled Stark but the attack was not for immediate kill. Thanos wanted to watch Stark suffer to death. That’s why the weapon did not impaled Tony’s heart or any other specific organ that could result death. So he was injured badly but not enough to die immediately. As we have seen Tony was coating nano-particles on his injury.
  2. Thanos already had the soul stone while fighting Stark. Now when Sorceror Supreme made a deal with him in exchange for Tony’s life, it could have been Thanos spared Tony’s life using soul stone.
  3. Or it could be all part of the Strange’s strange plan that saved Tony. Considering, Dr.Strange’s past record in MCU and the rumor about Avenger 4 being a time travelling movie; it could be Strange who did some trick with the Time stone before giving up which also saved Tony even after being impaled. Remember his last words “It’s the only way…”.

Now, as MCU has not cleared the specific reason, these are all possibilities. One of these three or all of them may be the reason of Tony’s survival. I guess, Avenger 4 will clear all the doubts. So Let’s wait and watch.