Wouldn't it be a lot easier to listen in on the plans and get close to the actual leaders, rather than some lowly prison guards, by turning into a rat and just blend in with all the other rats that are freely scurrying about the place?
I support the theory that he is stuck in his bear form as a trauma response. He goes into fight or flight mode and when in that state he instinctively goes into his bear form because that is where he feels most comfortable and safe. The narrative strongly supports that this is something that happens to Halsin when his instincts take over.
You don't have to call it incompetence, it's a character flaw, which can also make a character more interesting.
