now you just know they're gonna get caught watching the two one day in the mess and giggling and blushing while john gets paranoid and rodney is oblivious

Yes! And then when Rodney finally notices, he'll stomp over to them and say, "What?!" in his most intimidating voice, but it will completely fail to intimidate the ladies because they'll notice the hickey peeking out where the zipper on his shirt slipped down, and they'll giggle more and he'll get that bewildered look on his face and John will put a hand on his elbow and pull him away, and they'll all stop giggling and sigh moonily.