The thing is: in a gym battle, there is room to make a bad move/prediction/calculation most of the time, if you stick to a minimal team of 6-7 members. I got through ep. 14 with only 7 mons, of which I trained Metagross mainly for the icy field. I started in ep.10-11, though, so things might've gotten more balanced. (no, I didn't use gyarados nor blaziken) But yeah, you mainly should save often (in case you need to scout some bosses), and think of a way to get around it.