Did the Gman.............?!!? *SPOILER*

[jerkasaur]

^The "peculiar room with huge screen a desk and chair" is most likely the entrance lobby to Anomalous Materials in Black Mesa,

not really, no.

That 'particular hallway' has Kleiners notice board at the back , use noclip and go check it out

yeah I just found that out this morning. I'm thinking, why is it needed anyway?
there's a difference between the transmission in ep1 and ep2 too, in ep1's transmission the Elite guards fire orbs but in ep2's transmission they don't. (and ofcourse, the hunter model has changed too)