You can check my student equipments in the description. You want your students to deal enough damage to take down the enemies in 1 EX. Stage 3 or Tier 3 is similar to tier 4 anyway, the enemies can heal.
It’s not about the level, you really need students with specific skill and use the right tactics, I’m at level 85 but stage 3 also fuck me up. I can pass only 2 teams