When I get out of here, if I’m ever able to set this down, in any form, even in the form of one voice to another, it will be a reconstruction then too, at yet another remove. It’s impossible to say a thing exactly the way it was, because what you say can never be exact, you always have to leave something out, there are too many parts, sides, crosscurrents, nuances; too many gestures, which could mean this or that, too many shapes which can never be fully described, too many flavors, in the air or on the tongue, half-colors, too many. But
The uncertainty of the narrator - the handmaid who was given the name Offred - shows us how much she is traumatized by the events of the book. This quote doesn’t look like a precise description, more like a reflection: she tries to settle down her thoughts and memories for herself too, not only for her future audience.
She tries to tell her story, but she clearly understands that she is unable to grasp the whole picture from only her perspective. Offred clearly says that her story is a reconstruction, that may be not complete truth and may be distorted by her own understanding and memories. Also, we see how rich her language is here - in Gilead, the imaginary dystopian country the story takes place - women aren’t allowed to read and write, so here Offred uses all the possibilities of her language to express her feelings and just practice her narrative skills.
The ambiguity of the words “When I get out of here, if I’m ever able to set this down…” adds some intrigue to the quote. In the end of the book it is said that the text is transcribed from the tape. Can it mean that the handmaid managed to run away, or was this tape just preparation and the final narrative wasn’t “set down” yet? The only thing we can be certain about - Offred, as lots of people in the unbearable conditions before, desperately tried to leave something after her: her story, her personality - to be known to other people. She hoped to escape, but leaving tapes and notes was also a way to escape at least partly, letting the others know her true name instead of the humiliating nickname Offred, her story, feelings and hopes.