Room C3 (1) "Crash"

There's an emitter aiming right at the only receiver required to open the door. The only problem is the second particle that collides with the first!

Look for a way to prevent the collision.

In particular, seek a way to redirect the second particle.

There's a force-field in this room, but it's disabled. It might do a good job of blocking the second particle.

Once the force-field's switched on, you can't turn it off again, so make sure you're on the right side of it when it activates.

Use the top-right emitter to activate the force-field, but walk to the far side before it switches on. Then fire the other two emitters to open the door.