Lily waited as the professor went over how one could get into the chamber. Most of it was stuff that the ravenclaw already knew due to reading her textbooks. But the part about not having to know parseltongue to get in was new information to Lily.

And now the professor was speaking to the sink in parseltongue. We had better not be going into the Chamber... Lily thought as she started to shake in fear. Sure, there was no longer a monster, but it was still creepy to be entering the chamber that was so famed in history.

Why... the redhead didn't want to enter the chamber. How would they get out since there was no ladder or anything around to get them out? But they were going in for sure. So Lily let a few go down before her, so that 1. she could learn the incantation to light your wand and be able to test it out, and 2. she wouldn't be all alone down in the chamber. Once it was her turn to enter the chamber, Lily lit her wand using lumos and carefully slipped into the tunnel down to the chamber.