Suffocation, CO2 poisoning.
One of the things I had to bother to research was the consequence of being shut up in a hermetically sealed space. (No air or other gases can get in or out). Particularly, how long can you survive in a portable hole, a sealed room, or an underground chamber sealed off by a cave-in? As it turns out, after considerations of the partial pressures of oxygen and CO2, it isn't a lack of oxygen that will kill you but an over abundance of CO2 that will poison you to death. As such, when you hear people talk about how much air or oxygen they have in such a space you should know the real concern is the CO2 levels being given off by respiration, combustion, or other sources of CO2.
As it turns out, a 10 X 10 X 10 foot space, or 1,000 cubic feet, will be filled with a lethal concentration of CO2 by one resting human sized individual in just 24 hours. (The CO2 level reaches about 1% in that time). Moderate activity will cut this time to 12 hours, and strenuous activity to 6 hours. Thus, 8 hard working individuals in such a space will die in about 6/8th of an hour or 45 minutes. Naturally, this would make travel in an extra dimensional space possible since many people could survive the time taken to plane shift or teleport to a new location. It is, therefore, possible to move relatively large groups of people using this technique, provided the individuals who are outside of the space, plane shifting or teleporting, don't run into any problems preventing them from releasing their passengers in a timely fashion. Remember that plane shifting on the border ethereal plane just increases your movement rate by a factor of 100, but the deep ethereal by about 10,000 - or to more safely travel, about a factor of 1,000 on some middle ground. The higher speeds may be necessary in order to get the group out of the portable hole before they die.
Say 8 people, resting, will use the air in a 10 x10 x 10 space in 3 hours. So you can only get about 720 miles in the near ethereal, but 7,200 miles to 72,000 miles while in the deep ether. Naturally, since Orlantia's circumference is only 1700 miles or so, one can get anywhere on Orlantia in that time if they go via the deep ether.
In case you are wondering, it is assumed a movement rate of 12" will result in 24 miles in 10 hours of travel. This is 2.4 miles/hour. For 3 hours, this will result in 7.2 miles on the PMP, 10 times that or 720 miles traveling via the border ethereal plane, 10 times that or 7,200 miles traveling the deep ether, but doing it carefully so as to subtract up to one encounter roll, or 10 times that or 72,000 miles without the caution, perhaps risking 3 encounter rolls for an unknown path. But if you are more interested in the mechanics of planar travel, you should follow the link below.
© May of 1999