Good video except for one (well several) things.
One - the 530mph* is the
Taken directly from the manufacturers own spec sheets
Not maximum safe speed, nor even the maximum operational speed. The typical cruise speed, something that is the speed that it will normally be operated at because it's a good speed for fuel effiency and the level of wear on the airframe and engines.
There is also the fact that you can typically go a fair way over the "safe" speed before the aircraft suffers immediate damage (let alone the speed the operators expect aircrew to stick to, which is a speed usually chosen for minimum maintenance, maximum safety and running cost reasons - it would be a really poor design for a vehicle that is intended to carry several hundred humans if it suffered catastrophic structural damage the moment it went over the typical speed for it's altitude, for one thing if you're flying at the typical cruise speed, lose control and enter a dive you really don't want the wings falling off before you have a chance to pull out of it (a manoeuvre that will put the airframe under more stress than just the speed increase).
I would also point out that the take off speed for a 767 can be 210..
I won't even go into the question of how much the person on the phone actually might have known - she doesn't sound sure (and is a spokesperson, not a tech*), and the guy's own assumption of "250mph" which she laughs at is only about 25% above the take off speed of the 767 with a tail wind...
It basically sounds like the guy rang up the press office rather than anyone technical.
*IIRC the actual airframe is rated to something like another 100mph on top of that.
**for example she says "we don't have much on that" - which an aircraft tech (or even pilot would have), She also misquoted the companies own fact sheet for the 767, by basically stating the speed of 530mph at 35k feet was the safe speed, when it's an operating speed (massive difference)