Well, as it happens a lot of times with us, it started as a joke, MiB actor is really hot after all, then the joke's on us when we developed our time travel AU, that was the first time we made him want Jack explicitly. So as we gave it more thought we noticed how Terry O’Quinn in his MiB role basically looks like he wants to eat Jack more than murder him. Pity Jack doesn’t make it easy for him, despite how at the beginning MiB turned into Christian sent Vincent to him in the bamboo forest and later helped him to find water? He even says, when Jack asks him about it, that he did it because Jack needed it! Like, appreciate a bit that black smoke who murdered the pilot and almost made you fall from a cliff, Jack! And then there are the extra scenes together with Jacob where again MiB basically stalks Jack. So yeah there a lot of toxic attempt at murder but there are also a lot of toxic attempt at make you survive. Romance can be complicated sometimes.