The concrete roadblock was about chest high and about two and a half feet thick, parts of it are anchored to the ground. It would be normally scalable to any Nepleslian not in Power Armor, but the weight and inflexibility of the suit made it impossible to vault or mantle over. These shortcomings can be easily rectified by powered limbs, thrusters or firepower, which the Greenhorns may or may not have.
One of the cars had repeatedly tried to ram its way through the roadblock, the roadblock is fine but the car is not. A parked monster truck about ten cars to the back may be more suitable for the job, indeed the cars behind it looked like they were forced aside, the cars infront of it would have been too if the driver wasn't stumbling around nearby being a recently infected. Speaking of which, the zombies in the area may have matured somewhat since the marine's arrival, and are starting to eye the Greenhorns suspiciously.
In the meantime, if something could be accurately described as a bullet rain, P3C Jack Hayden is definitely feeling it. Droplets of all shapes, sizes, grains, trajectory, rate of fire and muzzle velocity were bouncing off his durandium armor. While thankfully nothing rated against PA armor was being thrown at him by the fifty something zombies, some of the larger stuff feel like pain(t)ball hits as they transferred their kinetic energies through the hull. As a testimony to the sheer amount of lead coming from the opposite direction, the Greenhorn's panzerfaust shot never made it. The warhead exploded midway through in a flashbang-like effect as its anti-matter payload mutually annihilated the air particles it came in contact with. As with a regular flashbang, the hostile crowd was briefly stunned. The mini pellet-storm Jack returned downed two zombies permamently and pissed off a few others. The crowd was still beyond the shotgun's effective range.
The bullet rain stopped for now, but the damage was done. A bullet was lodged in the PA's right elbow, no permament damage but it hindered the pivoting of that joint and would require some fingerwork to clear (courtesy of the left hand most likely, that arm was spared due to its mounted guard). A hairline crack can be seen along the glass covered visor of the left monoeye. Also, Jack may not be sleeping on his front for a very, very long time but for the briefest amount of time, he had bought a few precious seconds to the senators.