Portable Hole suffocation

[Crake]

So I was reading the rules on the portable hole, because I was thinking about smuggling some people using one, and it says that it has enough air for 1 medium creature for 10 minutes... I thought to myself "Hang on, what do the suffocation rules say?" Upon looking, it says 6 hours for a 10x10x10 cube. Now a portable hole is decently close in size to a 10x10x10 cube, being 10ft deep and 6ft across. Upon calculating the exact numbers (10ft*3ft radius*3ft radius*pi) you get about 282 cubic feet, vs 1000 cubic feet in a 10x10x10 cube. Multiplying the percentage (28.2) by the duration (360 minutes), you get approximately 100 minutes of air, so it seems like someone accidentally lopped off a 0 somewhere along the line. Now, admittedly, a medium creature would take up more proportional space in a portable hole, displacing more air, but it seems like 10 minutes is really far off, unless I've messed up my calculation somewhere along the line?

Just looking for a sanity check here, I'm fairly sure I've got my numbers right, but I want someone to double check for me.

[flappeercraft]

Well it must be a case of miscalculation on WoTC's part, its not uncommon. But raw is never wrong

[Drakevarg]

Perhaps the atmosphere is just thinner in a portable hole? We're not exactly given a thesis on the physics of extradimensional storage spaces.

[Fizban]

You'll notice that the Bag of Holding has the same 10 minute air supply. I believe it's simply the traditional number.

[Bohandas]

Perhaps the atmosphere is just thinner in a portable hole? We're not exactly given a thesis on the physics of extradimensional storage spaces.

Or maybe it has poor air exchange with the outside while it's open; so to get 100 minutes of air you'd have to leave it open for a while or give it a good shake

[Vaern]

Perhaps the atmosphere is just thinner in a portable hole? We're not exactly given a thesis on the physics of extradimensional storage spaces.
Brilliant. The extradimensional space must have an air density proportional to that of the air outside of it divided by its size. For example, say a bag of holding's external volume is one tenth of its internal volume, then the air inside of it will maintain one tenth the density of the external atmosphere's air.

Realistically, the creators of these items probably didn't bother with the math regarding suffocation rules, and only added the 10-minute restriction to prevent people from using bags of holding and portable holes to smuggle people unnoticed into places they're not supposed to be. It falls into the category of, "It's magic, so we don't need to explain it."

[ATHATH]

Maybe the bag absorbs air for some reason?

[The Vagabond]

The bags don't actually exist in their own dimension, but rather exist in between dimensions, where there is nothing but void, including nothingness. The portable hole opens up a small area of this dimension, contained with a magical veil of some sort. This place is so completely devoid of oxygen that the veil cannot stop it from leaking into the vacuum that it has created.