The procedures for ditching are diffrent from an a/c to another.
I don't fly 737, but I do fly B777, A330, 340, mostly long and ultra long haul. The rule is that if the door has a slideraft u keep it armed and u open it, as the slideraft cand be detached from the a/c and used a raft. If the door has just a slide, the drill says to disarm, block the doors and redirect the pax.
However, if the situation is catastrophic and you cannot open other doors, you open, for example, LR3 doors in 777 to evacuate. If u have to get "t.. h.." out of there you have to use any possible way.