That creature is called "Garrador", and those things in his arms are actually claws (hence his name, considering "Garra" is Spanish for "Claw"). But well, that was just a curiosity.
Garradors are blind and fairly easy to defeat once you know that. They die with a few shotgun shots, but remember you must aim for his spine (in his back, where the Plaga is exposed). In this specific case, you'll notice a couple of bells on the walls. Those monsters move by what they hear, so shoot a bell and he will automatically run towards it. Keep in mind he will end up destroying it, so get behind him and shoot as fast as you can.
If, however, he manages to destroy all the bells before you kill him, relax and simply wait. Do not move your character. The Garrador will just roam around, and you can wait for him to turn his back. Oh, finally, keep Ashley away. She will die with a single attack.
Best of luck, hope I've helped.
againstall has invadedBECKY = 10/10