>>50742070Another update:
In the back streets of Castelia City, accessed by the sewers, is a trio of trainers that you fight in a row. First a Single Battle, then a Double Battle, then a Triple Battle.
Since I only had two Pokemon remaining after the second battle, the third trainer actually didn't fight me right away, which let me heal up.
And my reward for getting through these fights is the Leftovers, which is pretty nice.