After entering the cathedral in Chapter 2 of Leon's Campaign, you'll have to solve a series of puzzles. After ringing the bells, you'll return to the main room and encounter your first Lepotitsa enemy. It will spray gas everywhere and start turning the people into zombies. Your job is to save at least two ladies from becoming zombies.
The only real strategy for this fight is to fill the Lepotitsa with lead and take it down as fast as you can. When it takes enough damage and kneels, run up next to it and follow up with to do some good extra damage. Try not to get too close when shooting or it's gas attack will deal a big chunk of damage. There's a bit of luck involved as far as having two females survive, but as long as you're fast, you shouldn't need to worry about missing this.