Why do you think they're all afraid of doomguy? Did Hayden show them a buncha footage from the Mars facility of his ripping and tearing? Fight like hell indeed.
“Attention UAC personnel, this is Doctor Samuel Hayden speaking. If you see a scary looking man in green armor and a lot of guns just stay out of his way. He’s a borderline immortal demon-slaying god. Thank you, please have a safe and productive work day.”