Which bit are you missing here?
You said "Better built" and linked it to mid air break ups. You misquoted the book by Mr Wakelam, to make it appear that way. I disagreed. Not only is it wrong its an insult to all the people that built them to suggest they did a substandard job against the Halifax.
We got bogged down in things during which I point out I don't necessarily agree with him, or ORS reports of the time based on information we have now that they didn't have in January 1944.
Regardless, the Halifax wasn't better built, and no doubt they might have had to change their opinion on which was the stronger too - as just over a year later the Lancaster had already lifted the 12,000lb bomb, and in March 1945 the 22,000lb Grand Slam. Not bad for a weaker airframe.
As for not blowing up when hit, it might be worth you researching the 'Scarecrow' myth. I mentioned earlier I have friends from two crews both that got hit by upward firing cannon and both aircraft blew up. It might be coincidence but there seems to be quite a few others that did as opposed to flying along shedding parts bit by bit. Yet according to you - they "did not blow up".
With the hatches, be specific - which ones? The ditching hatches on top of the fuselage of the Lancaster are ridiculously small, but the three for bailing out of are quite large (rear turret doors, under the bomb aimer and rear crew door.)
Regards,
Rich