I believe you're talking about breaking into Old Olney for the Tesla Coil in Fallout 3? Either this or the base with the Enclave Crawler? I literally just finished that part, but don't understand exactly what you're talking about.
By target, are you referring to the Waypoint arrow? If you expand I could help better, but I don't understand you fully. My guess is that you're on the wrong floor.
Again if this is like something else with Broken Steel in the name and just so happens to things called Deathclaws, I'm sorry, lol.