wrote:

Standard practice is to wait until you have a positive rate of climb
before raising the flaps. Raising the flaps if the airplane was on
the verge of a stall would be a big mistake. Lowering the nose and
applying full power would be the best course of action, and once a
positive rate of climb could be achieved, then the flaps could be
raised.

There is some debate about that. For a wing stall, you are correct,
however, some have pointed out that the PIC's experience was recently on
Saabs, which can see tail stalls in icing conditions - the Q400 isn't
subject to tail stalls. A tail stall is most often first seen when the
flaps are extended, and the effect is for the nose to drop. The reaction
to a tail stall is to retract the flaps, and pull the nose up. Was that
what the captain was reacting to?