The restricted zones are wildly inaccurate in the Firefight West Outskirts scenario. If you're playing as Security, try leaving the spawn to the right of the back wall of spawn. Even though this path will take you quickly on a valid route to C, you'll get a message that you've left the playable area and will be killed in 10 seconds. The tactical map does not show you in a restricted zone, and the boundary is in a strange, middle of the street spot. I also noticed it on the road leading up to C. In some sections, you'll get the message saying you are leaving the playable area even though you are not in a restricted zone.
Check out 208c2ed2-a5e9-4c98-b2c1-eea51db9811e from Glanton's perspective, last round two rounds of the match.