Then you can freely loot the shop of all of the items. Every Brax on the same level will also be angry at you and will attack you on sight. On other levels they will be normal.

You might think, "If I can kill all three Braxes on one level I can steal everything so easily. Yay!" It's not quite that simple. As soon as you leave the first shop the game starts spawning an endless stream of Dread Collectors. They look like Big Red and are about as powerful. However, they don't just punch you in the face. They also cast toxic AOE spells all over the place. They quickly surround you and if you don't have a teleport, or a way to get them away from you, you are almost guaranteed to die. Later in the game, though, you can get enough armor and resistances to completely ignore their melee damage and the damage from their spell. But they are still a huge hindrance to movement.