Halo Infinite's campaign takes on more of an open-world approach for the first time in the Halo series. It brings many new things to the table as well as some returning features Halo veterans will be excited for. This includes Easter eggs and one of the first is the orbital guns at Outpost Tremonius by pressing a series of red switches.
To fire the orbital guns at Outpost Tremonius in the Halo Infinite campaign and activate the Easter egg, you must press red three switches, which show up on your AI scan, before clearing the base of all enemies. This will activate the guns which will then launch an airstrike, killing nearly all enemies in the base. Here is how to fire the orbital guns.
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Switch 1
This first switch can be found by turning right after the hangar door opens revealing the outpost. Turn around the corner of the base and head along the cliff. You will see some wreckage before reaching an armor core upgrade. Beside the wreckage are a dead marine and the first switch. Press this one.
Switch 2
This one is a little tricky to find, but if you look up along the cliffs on the right side of the outpost, you will spot a crate in the wreckage with an orange piece. The second switch is behind this crate. You will need to use the grapple to climb up to this one. Once you have reached it, activate the switch.
Switch 3
The third and final switch is easy to find. It is located beside the orbital cannons on the far right side of Outpost Tremonius. Simply grapple your way up to this one and activate the switch. Once you have done this, an airstrike is called in, killing all the enemies on the landing zone.
For more information on Halo, check out How to claim the Halo Infinite Game Pass Bonus Rec Packs and How to redeem codes in Halo Infinite on Pro Game Guides.