Ah yes, there was actually a white portal you just pass through, hypothetically, before that region. The white portal would set your gravity to 0, so you would not be able to stop the push without the friction from the ground. Now obviously you are smart, you probably have figured out that there is a green portal you could dash into to the left, setting the gravity to normal and thus experiencing ground friction. Though for non-gamers, that part is pretty hard.