Thinking about this in relation to Azzy's canonically having military experience -- leading a platoon, which if the Heavenly Host is organised along similar lines to the British Army, means 25-30 angels commanded by (the equivalent of) lieutenant or second lieutenant -- not *super* high in the commissioned/officer ranks, but not bottom-of-the-barrel by any means.
And it's very likely that he served with distinction -- however Heaven defines that -- in the Great War, because a posting like Guardian of the Eastern Gate is not the kind of gig you give to an incompetent lollygagger. It's probably part of how Gabriel sold Az getting this position to Head Office (though his *actual* motivation for giving Azzy the job might well have been to get him out of the miserable, suffocating environment of Heaven).
So there's this cute, soft, cuddly, fluffy, very kind angel with military experience at a command level and involving a not inconsiderable amount of active combat (likely at close quarters/melee range; swords, hand-to-hand etc) -- the Battle of the Bookshop is only the most overt indication of this; as the above post points out, it comes through subtly but noticeably in Aziraphale's overall physicality throughout the show.
I am reminded of one of those 'goes hard as heck but comes from a tumblr shitpost' phrases -- "It took a lot of violence to become this gentle." (paraphrased)
