Look for a way off the island is a mission in The Lost Frontier. After chasing Phoenix, who kidnapped Keira Hagai and stole the eco seeker, Jak and Daxter were led into an ambush and once again crashed on Brink Island. Without Keira's mechanical expertise they could not repair the Hellcat and had to look for another way to get off the island.
Progressing through the first path of the mission is fairly linear; proceed to open a nearby door and grab the new Scatter Gun mod for the Gunstaff behind it. Its short but wide range will be useful for clusters of enemies nearby. After swinging across a pair of poles and climbing stone pillars up to a higher ledge you will run into a Precursor idol; approach it to gain a new eco power. You will now have gained the eco amplifier power, which can be used by pressing (on PlayStation 2) or (on PlayStation Portable).
Activating the amplifier will cause Jak to fire a large red sphere which travels forward until it hits an object. By itself it is harmless, but will detonate when fired upon with a weapon, dealing damage within a fairly large radius. Use it either at close range in combination with the Scatter Gun to rapidly deal large amounts of damage at close quarters, or hit it at a distance with the Blaster in an attempt to stay out of harm's reach from enemies.
The amplifier can also be used to destroy large boulders and other blockades. Progress through the level until you run into sawbots, small robots that use their treads to close in and attack with large groups, making them a good target for the Scatter Gun–amplifier combo.
Be wary of more sawbots ambushing you from behind trees, and continue until you encounter a chest. Open it to find the Brink Field Jacket, which raises your maximum hit points. Shortly after you will encounter tripodbots—blast bot look-alikes that have a powerful ranged laser attack. Try to avoid being targeted by them while fighting at a distance, and instead close in and keep attacking to continuously lock them into flinching from the damage and preventing them from counter-attacking.
The remainder of the level features more combat against sawbots, several more platforming sessions involving swinging on poles and use of the amplifier power to destroy boulders. Keep notice of narrow paths through valleys, as sawbots will use these to attack you by trying to crash trees on top of you. The end of the mission is reached once you have entered a larger clearing with a force field at the end. Defeat the final wave of tripodbots and sawbots as they try and stop you to be able to disable the force field and explore the treehouse in the area behind it.