Why in the prologue people are astonished by "floating rocks"? Why do they point it out?

That's wrong though. He's an older man who just went through a huge fire fight and was thrown off a mountain. N7 training or not, he's not a prime candidate for holding your breath WHILE delivering his last words. He has a whole monologue that Ryder doesn't hear. A thing about speaking is that you may, from time to time, need to breathe in to continue saying what you were saying.

Oh, yeah. That too, that's what Alec DID. You can SEE this happen from Alec's POV.

my point is that he did not need to and it made no sense to. There is no point to it. And speaking doesn't expel all your breath at once.

No, no no. Your point was that the air was sucked from his lungs based on a wiki article you half understood. And then it was that Alec didn't breathe the air like Ryder did so he wouldn't have asphyxiated. Then it was that Alec would have held his breath. Now its Alec SHOULD have held his breath.

And speaking doesn't expel it ALL. But just see how long you can speak before you need to take a breath.

Now do it as an aged man who just fought through an army and was hit by a blast from a teraforming machine.

You make less and less sense. Either way, Alec was going to die. He wanted to lament to his son instead of stubornly clinging to life for the slim slim chance that he might SOMEHOW (magic maybe?) survive that situation.

1. I did not based this on a wiki article. Just my knowledge on boyle'a law.
2.during that I did not take consecration to the planet atm.
3.I long since past on that theory and I just question how Ryder and Alec passed out so quickly on a planet with an atm simular to Eos.
4.We went into detail on what was in the atmosphere when I brought up argon and nitrogen is in the atmosphere of habitat 7. Two gas that are normally non poisonous but pointed out to cause Asphyxia in closed environments or in heavy amount.
8.it was then pointed out the Ryder did breath heavy amounts of it, which is true...
9. But still does not explain Alec who did not breath heavy amount of it in the length of Ryder.

I not going on about the vacuum causing this. That end when habitat 7 atm was stated to be 2.3 atm. My question is now why Alec passed out so quickly.

sure you have shorter breath but it's not seconds long. And remember, people in ME have longer peaks of enderance. Age is not going to be an effect on his performance.

he left that detail for Ryder before they left the milkyway. He even added more things before he went on habitat 7.

Alec passed out so quickly because after you see Ryder Jr. Pass out Alec goes on speaking for a few moments, and is struggling to breathe as he does. This is shown in Sam node, via Alec Ryder's memories. Alec would have succumbed far sooner than Ryder jr because he's far older, and had just lost the biological benefits of his SAM. 

They BOTH survived longer than expected while breathing in asphyxiants under heavy atmospheric pressure-and I'd say that was due to their rigorous training.

and as I said before you have to breath it in first.aka expel all the oxygen in the blood stream.

Ryder when out quickly but talking do not dispel all air in the body all at once. It would lessen his team but not to seconds. Also, with how regression is in ME, Alec'so age is notngoing tonbe a factor. Heck, going on based on he fought once can say he is in a bettwr condition then ryder was at the time do to SAM.

OK never mind. I just figured it out. Alec passed out quickly because he transfer SAM. I forgot, Ryder is so connected to SAM that if he disconnects forcefully he\she can pass out and \or die. The same could be true for Alec.

1. I already figured it out.
2. SAM would make more.likely he would.not pass out.
3. Human is ME can live up to 200 year old and 60 is considered and extended 30 in ME for humans. This is in the codex from me1.

Nah, ultimately, the Hyperion hitting the Scourge and Alec dying could be explained by science, unfortunate circumstance, bad decisions, etc....

I got WAY bigger issues with the plot of MEA.