How did Ivankov and Inazuma survive Magellan?

Question

So, in Chapter 545, Ivankov and Inazuma hold off Magellan. And they get covered in poison (at least Ivankov does for sure).
How do they survive that? Maybe Ivankov I can understand, but how can Inazuma be defeated by Magellan and still be able to feel better enough, even with Ivankov's help, to help in the Marineford War?

Answer 1

The following details are taken directly from the wiki page on Inazuma: (emphasis mine)

After a brief fight between Luffy and Blackbeard, Inazuma and the others managed to reach Level 3: here, he cut the stairs to level 2, following the instructions of Ivankov, who stayed to battle Magellan. Refusing to follow the other prisoners to Level 1, Inazuma stayed in front of the stairs waiting for Iva, but he was reached instead by Magellan, who easily defeated him with poison.

Fortunately, Inazuma was picked up by Ivankov. Though both of them were barely alive after being defeated by Magellan's poison, they quickly caught up with the rest of their allies on the top of Impel Down using Iva's Hell Wink to propel them up the prison. Having caught up with the rest of their allies, Inazuma and the rest were not given a moment's rest as Magellan came at them with his most powerful technique. Heeding the advice from Jinbe over the Den Den Mushi, they all hung on to Iva's huge head and using another Hell Wink, blasted their way into the ocean just as Magellan cornered them all at the pier. Though this move seemed foolish due to the waters surrounding Impel Down being a Sea King's nest, they were fortunately saved by a school of whale sharks that Jinbe called for aid.

So yes, they both were defeated by Magellan's poison, and barely escape to the ship. Now, the next section in the page, about the Marineford War states: (emphasis mine)

Inazuma was treated for his poisons on the escape ship to Marineford. Ivankov decides not to use his healing and tension hormones, claiming that Inazuma is a very important revolutionary and this process shortens the lifespan and may cause various after-effects. Iva decides just to wait until Inazuma is recovered.

Near the end of the battle at Marineford, Inazuma emerged from Ivankov's hair, having been hiding in it all of the time since the boat crashed into the battle. He then used his Devil Fruit powers to create a walkway to Ace's Execution platform for Luffy.

Similarly, from the page on Ivankov:

Ivankov revealed he used Healing Hormones and Tension Hormones to save himself from the poison, but he did not want to put Inazuma through the same thing.

So, Iva cures the poisons to ensure Inazuma is out of danger, and then doesn't use the hormones on him. Hence, Inazuma is out of action till the end of the war, and even then doesn't really fight head to head with anyone.