Miasma & Holding Your Breath

[Aluvir]

Hi, everyone! This is my first forum post, although I've played pathfinder & starfinder for several years now. Apologies if I have posted this in the wrong place or have otherwise violated forum rules.

Recently my starfinder group encountered "miasma", the 4th lvl mystic & witchwarper spell. The text of miasma makes it clear that it bypasses armor environmental protections. For a fourth level spell, the ability to inflict possibly nauseated & definitely sickened on a 60ft diameter sphere of players / npcs sounds really great!

However, it then says: "A creature that breathes in the miasma must attempt a Fortitude saving throw", with the bulk of the spell's effects applying if one passes or fails the fortitude save. Some individuals believe this is merely flavor text, while others, myself included, argue that it's a valid mechanical description.

In starfinder's CRB there's a lvl 2, 740 credit aeon stone (iridescent spindle) that negates the need to breathe.

Additionally, starfinder has mechanics for holding one's breath, although it doesn't specify what action this takes.

Finally, there are specific races, like androids, that are explicitly stated as not having to breathe.

With those points, my questions are:

1. Would miasma affect a non-breathing race or an individual benefitting from the aeon stone?

2. What action is holding your breath, and for a breathing creature, would holding your breath protect you from miasma?
Is it no action cost & can be done at any time?
Is it a reaction, capable of being a response to a casting of miasma?
Is it a standard action by default? Being a standard action or even a reaction suggests that entering water unexpected would have you immediately suffocate.

Thanks for any help in clearing up miasma & holding one's breath.

[Garretmander]

I am of the opinion that it is entirely flavor text. If environmental protections don't protect you, holding your breath won't protect you either.

If I were to assume that it is rules text however, I would assume it only means that creatures with the 'no breath' universal creature rule are not affected by the spell. The aeon stone does not grant you that universal creature rule, so it wouldn't help.

So,

1) Maybe not for someone with the no breath universal creature rule. It would affect someone with just an aeon stone. If it affects you through enviro protections, it'll affect you through magic partial enviro protections.

2) Based on the suffocation and drowning rules, I'd a creature can hold their breath whenever they want for the specified time. Based on this spell bypassing enviro protections, that won't help you.

I believe it to be no action required until you pass 2x CON score rounds of time.