Lu Li wasn't able to move much from his position – otherwise, the Summoner would lose sight of him and stop summoning.
This was quite a strong force, but Lu Li didn't really have to participate dealing damage. Instead, he could take some time to tell Water Fairy about the bug. In another instance of the same dungeon, Water Fairy was leading an elite group of players to exploit the same bug.
Lu Li hadn't really thought of keeping this secret to himself, but it wasn't because he was feeling particularly generous.
When Drizzle Court had become an ally, that should have been enough reason to share some resources. Drizzle Court had a 1/3 chance of running into Glory Capital in the next round. It wasn't realistic to expect them to defeat Glory Capital – after all, they were weaker than Blood Red War Flag. Only Peerless City stood a reasonable chance, but the quality of their players was still weaker.