Red Flashes.

[Laff]

I'am pretty convinced it's the Combine advisor speaking to you. I opened GCFscape and noticed the advisor had his own voice files...I listened to them, and they sound EXACTLY like you would hear when you come across those pods, except they are mixed and are all bunched together.

 

[Andy018]

The red flashes are a psychic weapon this is confirmed in the commentary in that area. and will feature in episode 2.

Also the white escape thingies are confirmed to feature heavily in episode 2.... too

 

[MorganFreeman911]

leme guess, commentary?