You are carrying two traveler sacks and get attacked by an animal. You cannot draw a weapon while carrying the sacks, you cannot drop the sacks; you must waste time emptying the sacks, which probably means dropping their contents on the ground, then putting away the sacks or dropping them on the ground ....all the while being attacked.
Why cannot we use tools or weapons while carrying the sacks? Precedent has already been set within the game - you can ride a horse while carrying the sacks, how are you holding the reins? You can carry a log, barrel, crate, chest, wheelbarrow, even a rowboat, overhead while carrying traveler sacks - how? You can carry all these things ...but not a tool or weapon?
Perhaps add several leather straps to the recipe for traveler sacks to account for shoulder straps for carrying them, there is plenty of real world evidence of this being done for centuries. Shouldn't be that difficult to create and would be a welcome addition.