If you have a gun that shoots out multiple shots, it’s possible to get them both low and then line up a shot with both of them and have them both die on the same turn to different bullets. Kinda involved, but it’s the next best option of you dont have good grenades, normality, or really high quickness.

Or you can do my favorite: proselytize one and then kill the other. Congrats, now you have two allies!