What is the pressure difference between the inside and outside of a plane?

Commercial planes fly at about 10,000 m, where the air pressure can be taken as effectively zero.. I understand that they are pressurised to have the same pressure as they would have at altitude 3,000 m . Which means that the difference between a high flying plane and the outside air pressures is about 2/3 of an atmosphere - about 10 lbs/inch^2 ( Sorry - I've never come to grips with metric pressure units - I'm guessing that this would be about 70 kPa )

For your bonus - you should be only interested in force being exerted, not the pressure. How many square inches is you broken window? Suppose its 10 inches by 10 inches - the force exerted would be about 1000 lbs, about half a ton, much more than we can resist by just holding on, but well within what a seatbelt can hold. And its only that high for a very short time, until the air pressures equalise.

When some plane lost the side of its fuselage, the passengers who fell out were not taken by the air rushing out of the plane but by the 800+ kph slipstream. The strapped in passengers all survived.