I can see it as his backup I guess, and he would leave it in place (but how that got missed when Harper has done so many repairs and the ship was retrofitted twice and all... still thin on their part.)

It may make more sense to you if you watch than it did me. I still can't see how he could do some of the risky things he did for the others and betray them (season 4 Tyr claims he was just using them, but that I still can't buy.)

I am a few episodes into season four, making slow progress but with my wacky sleep schedule, I have gotten in a few episodes a night (either before bed or when I wake up in the middle of the night and can't go back to sleep) so I got ahead.