I botched the last paragraph. Here is a rewrite:
Rapid recall requires neural mechanisms that overcome the slow speed and
unreliability of individual neurons. And rapid neural mechanisms that
result in a few rare errors have much better survival value than accurate
but slow neural mechanisms. If a child's recall of dangerous episodes is
slower than their actions, they will not reach adulthood. If they think "Oh
yes, now I remember, the mushroom I just ate was the same kind of poisonous
mushroom that killed my sister" their episodic memory will be useless to
them. It is therefore biologically necessary for recall of episodic
memories to operate quickly, even though the neural mechanisms that make
this possible may result in occasional false deja vu recalls.