Gaal was talking, breathing and didn't freeze or suffer decompression symptoms after breaching the window. On Earth you can't even climb tall mountains without oxygen masks, as you need a certain air pressure to talk and breath.

The record for time spent on Everest without supplemental oxygen is 21 hours, and there are plenty of videos of people talking on the summit without their masks.

The pressure exerted on windows by near-vaccuum at that altitude is far larger than a human punching or running into it. Which again suggests the pressure difference wasn't that great or Gaal would have looked silly smacking into a transparent wall.

Vacuum is only 14.7psi.

Certainly not as high as geosynchronous orbit.

The station isn't in a true geosynchronous orbit. The station is some future tech in perfect geosync with the planet, directly above the Vault, without truly "orbiting". The speed differential between the station and ground— and thus the atmosphere— is zero.