The pressure difference is a lot. 7psi is a lot, 3psi is a lot. The movie exaggeration is that decompression acts like a constant vacuum. There are 500mph winds at cruise, but it's not a constant vacuum.

This door plug that fell out is what, 6ft tall and 3ft wide? That's 18 square feet, or (18x12x12) 2,592 square inches. At a 7psi difference, it's holding in a force of (7 pounds per square inch X 2,592 square inches) 18,144lbs. I'd say that's a lot. Call the cockpit door half that surface area (and underestimating here) and it still has to resist a sudden force of 9,000lbs. That's like holding back the deadweight of two American sedans with drivers. Surface area of a vent is absolutely critical because the force of 9,000lbs on the door is so sudden, gas flow doesn't apply in human-tangible currents. You ever get hit by a calm wave? The water doesn't just trickle around you, it knocks you down first and flows around later. It's a gentler force, on the order of hundreds of pounds, and has a thicker fluid, but clearly doesn't flown like trying to hold a handful of water. Making 1/3 of the door a pop vent still leaves nearly all of the remaining 2/3 of the door under the same 7psi. It's still going to have to resist nearly 6,000lbs instantaneously. I mean, sport parachutes have holes in them and the pressure inside is still enough to comfortably hold up a human.

The other exaggeration is that you can keep fighting after decomp. No, you pass out in a matter of seconds. They are serious when they say put your mask on before helping others because if you try to mask your panicking kid first, after 30 seconds, you'll both be passed out. You can't just take puffs of that mask either, it's only enough to keep you alive, not enough to support strenuous activity.