Room B5 "Firewall"

Of the two receivers needing to be activated to open the door, one of them should be fairly straight-forward.

You'll need to use the factory to configure an arrow - one should be enough.

You'll notice you can only have arrows pointing right in the lower-left portion of the room and arrows pointing left in the upper-right area.

Therefore, you'll need to push an arrow over the factory and back again to be able to activate the receiver on the right of the room.

For the receiver on the left, you can deflect the particle that travels down the right-hand wall towards it, but you'll notice there's a problem.

The force-field switches on and blocks its path before the particle can reach the receiver.

Think about why the receiver switches on - can you prevent this happening?

Is there a way of blocking the particle that activates the receiver?

Deflect the particle that fires upwards towards the problem particle - the two will collide and the force-field will remain deactivated.