So I was using Face Poser to create a new scenes.image for Black Mesa when I stumbled upon certain choreography files. I loaded up BMS\scenes\c5a0a\gman.vcd. There I found THE choreography for the end of the Xen portion of the game. I believe this because the file had different speak events such as a job they agree…, you’ve proved yourself to be a decisive man, and uhhhhh employers. Don’t believe me? Look at it for yourself (I would post a vid of it, but I don’t have a decent enough screen recorder to do so). All you have to do is set up Source SDK for Black Mesa (go to this tread to find out how —>https://forums.blackmesasource.com/showthread.php?t=14702), open Face Poser ,and load gman.vcd.
Additional Notes:
As it turns out, the Black Mesa Devs were smart enogh to not package any G-man lines into the files so theres is no sound to be heard. As such, there are also few mouth movements to be seen.