The "friend or foe" mission had to be the most irritating 17 hours of my life and I was once locked in a room with 300 starving ferrets and Richard Simmons for 18 hours.
If this is the first "demon dinosaur" I am thinking of, then yeah, you gotta kill it. However...
"Friend or foe" irritated me so much that I had to make fun of it. Give this a read, it won't help you slay the beast but at least you know someone else feels your pain.