He wants to be a she, I thought of that possibility when Yuki refused to bath together, honestly the reaction to looking under the bedding made me think of a zombie bite.
I'm more interested in what the bots mission was, the infected only one of the 3 with some short lived virus, why not all 3, I would have understood taking the blood, but all bots broke down on the spot.
Maybe they wanted to force the variants to stay in one place, taking care of one of their own?
Whatever it is the humans controlling the bots in the bunker are not allies, tried to kill them with saucer, then kill/catch them with the golem, and now made one of them sick on purpose + whatever is happening in the shelter is enough to make a family escape outside.