The Giver and Jonas plan to have Jonas escape during the ceremony, when everyone will be busy so Jonas won’t be noticed until it’s too late.  The idea is to give Jonas memories to fortify himself, so he will survive the journey.  The Giver considers giving Jonas memories of escape, but tells him that every situation is different so there is no way he can prepare him for everything.  Unfortunately, Jonas learns that Gabe is to be released and he has to leave before he is fully prepared.

As they decide that Jonas is going to go out, The Giver tells him that he has the colors and the courage, and he will give him strength.  He plans to fill Jonas with memories of warmth, love, food and happiness to sustain him.  Jonas will need the memories of warmth, because he and Gabe almost freeze to death (or do freeze to death, depending on your interpretation of the ambiguous ending).  When they are starving, memories of food have to sustain them.  Unfortunately, since Jonas did not get all of the memories he runs out, and at the end it might be too late.