Just something that I noticed, and maybe not something a lowly inexperienced prisoner is expected to know, but lore-wise, only complete chainsword-amateurs parry attacks with the teeth, since it’s known to make them break off and fly every which way (especially if the opponent is also using one and does the same!).
The correct way to block with any chainsword is by using the reinforced side plate along the flat of the blade.
Would have been something Dan Abnett would have probably commented on had he ever gotten wind of it.