I figured this would be the best place to come and ask about this. It’s been bothering me ever since I found it years ago. When fighting the Nihilanth it transports you to different sections of Xen, one having water underneath, a few Vortigaunts and a Gargantuan. If you use the jump pads, you can throw yourself up onto a ledge high up on the wall where there is sat a scientist without an HEV suit.
Never have I found any explanation as to why he is there, whether it’s just a little easter egg joke or just an anomaly. I wondered if perhaps anyone could shed some light on it for me.
Reference video here: https://www.youtube.com/watch?v=vkgXNTpfj6U