Nathan and Morgana—now with Eorlagar—were to pass through the portal while the others would stayed concealed within Isabella's shadow until they were safely on the other side, at which point Isabella would release them at different positions around the area.
They had chosen this approach because none of them knew exactly what would be waiting for them when they arrived.
Nathan's memory would bring the portal directly into Irene's prison, but the dragons guarding her would undoubtedly see it forming.
If the entire team simply stepped through together, they risked emerging into an attack already aimed directly at the portal, leaving everyone clustered in one place the instant they arrived.
This reduced that risk.
Morgana and Eorlagar were among the strongest individuals present and could withstand an immediate confrontation.
Nathan, meanwhile, knew the prison and needed to lead them to the exact location where Irene was supposed to be.
