Why is water used in meth?

Not interested in synth, I just saw a documentary about it and I was wondering why would you add water to that mixture considering the fact that one already added Li?

To make the lithium react?

Sodium hydroxide is lye not li and water is a commonly used polar solvent with NPS like naptha that seperate where the water layer would contain the trash while the naptha would pull goodies to be evaped leaving them behind at least for an A/B or STB extractions last step. Meth synthesis is confusing and can be done many different ways. Like the above poster said adding water could be the catalyst needed to cause certain reactions leading to production.

Now this topic should not go further as it heavily borders on synth talk

Actually, Li is lithium. I didn't misspell the word Lye. Plus, the videos specifically showed they only used 2 caps of water. I think it's just a ridiculous way to die, and you don't need water to contain the trash (considering the fact that only freebases, in our case meth, are solved in NPS). The others won't migrate and they don't need a solvent.
If any moderator decides to close the thread, I'm fine with it. And tacodude is right, it heavily borders on synth talk.

In a shake n bake synth, it's the violent reaction between the Lithium and the water that kicks off the cook.