Portals

Okay.
Assume portals, as per the video game Portal, exist and are possible, etc. etc.

If you created one portal on, say, the floor, then another one directly above, you could theoretically fall endlessly.

Given this, would a human continually falling be at terminal velocity until starvation/death from stress?

Assume the portals have been made on linoleum dining room floor and a stucco ceiling. Would it be possible for the subject to move outside the portal to stop? If so, would the impact upon landing be enough to kill them?

God damnit OP now you've got me thinking of endless possibilities.

Addressing the last questions first, assuming there is no magical force field around the portals then there is no reason to believe anything can't get out, or in. As to whether or not you would die from impact upon landing, I'd guess it would depend how long you've been in the portal for.

If you imagine jumping the distance from the top of a residential house, you wouldn't die. When jumping from the top of a very large building, you'd die before you hit the ground due to the increased speeding up, pressure from the air on your body, etc. You'd have to read up on it.

Then comes the question of gravity. Given the portal has no base nor top, the gravitational pull is nonexistant due to there being nothing to pull at. As >>8 mentions, there would be some form of suction from air etc. Assuming the gravity is completely untouched inside the portal and unaffected by the outside world (the air vortex, etc. as mentioned), then when you stepped halfway in the portal, which way would you go?

Would you step in and, due to the loss of support from one side of your body, fall down (as you would if you stepped in a pothole), or due to the lack of any push or pull in any one direction from within the portal, would you go up due to the sudden loss of weight on one side of your body?

Fuck you, OP, I'm gonna have to go get myself a doctorate in a whole range of science subjects to fully work this one out.