What I don't see anybody mentioning so far, the real problem with the choice is, that one of them - let's call her ssica so that I won't spoiler and don't have to bother with the tag - is massively underdeveloped compared to the other, or rather we just saw her being bitchy as fuck. Other than the I letter trope so far, she doesn't really have anything going for her, and if the possibility to get back both later is dependent upon the choice here, which ends up being choosing her over the other, then by design it doesn't look good.