Anne Frank’s family was in an Apartment. The entrance was extremely small. A person had to stoop to enter. The small squad of one Nazi cop and a few Dutch cops, could have been wiped out with one carefully thought out ambush using one 30 round mag.
With a single AR or AK, it would have been completely possible to have killed them all. Even a Remington 870 could have done fine. The family could have left and vanished out a backdoor. Very possible they could have got away.
And if they didn’t, such goings on would have meant that the Nazi police force in Amsterdam would have had to do such investigations much more tactically, with more officers, and with better weapons. This would have taxed the murder machine further. Any participant in such a murder enterprise that is targeted slows the bureacracy, the more, and the more scattered through the machinery, the better.
Anne’s family needed an AK.
One guy with an AK could hold up a whole company of soldiers until they could root him out.