Gabriel ordered the retreat as he created an opportunity for them to escape by creating some sort of flashbang. Ark and Lilith were unaffected by the blinding light as they are beings of light, but the others were. Gabriel also used a skill that created a powerful pulse of light that knocked backed all of them.
Ark was about to give chase, but Vayu stopped him as it would not be wise to follow enemies that fly at a fast pace. The angels are also more used to aerial combat compared to them which is why they might lose. There might also be a chance for other angels to aid them which might get them captured.
Ark wanted to chase the angels badly, but he knew that defeating Gabriel and Pristina combined will be difficult. They already used their most powerful forms, but they were not able kill them. If Lilith was not here to contain Gabriel, then the fight might have a vastly different outcome.
