Hi there, I came here once for guidance on a stuck and worked, so I'll try it once more .

While playing in Entanglement, after joining with Alyx, we enter a elevator which lead us to a room full of enemies and force fields. After killing them, Alyx says "Hey let's go" and then nothing! She just doesn't move.

I tried F6+F9, replaying the part, but nothing... =/

Any help?

So she stays in the elevator even if you move ahead and kill all of the Combine?

Try restarting the whole chapter. If you don't want to bother playing it honestly again, just open the console (hit the tilde ~ key) and type "sv_cheats 1", then type "god" for godmode. Once you get back to where you were, type god again to turn godmode off.