Was playing versus yesterday, was on the infected team. The Survivors summoned the the chopper, and we got a tank spawn. They took down the tank, and then all four of them proceeded to stand under the ramp leading up the to helipad. It was like the battle of Thermopylae. They really couldn't be harmed much standing under there- they were shielded by a wall, and the metal on the other side of the ramp. The guy in front just gunned down the horde as they came to them. they could even shoot up through the ramp. Our only hope was to try and have a boomer puke or explode on them and let the horde wear them down.
However, after about 5 minutes, the chopper still didn't show. I got the thing on my screen saying I was going to spawn as a tank. Tank music started playing and everything. Then I respawned... as a boomer. This happened every time I died. Tank music... no tank, spawn as boomer. Eventually, no horde would spawn. They wouldn't even spawn if a boomer puked on one of the survivors. It was four on four straight up. They would pick us off from under the ramp as we closed in. Smokers were unable to pull them from under the ramp. Still no chopper. This literally went on for about 45 minutes. Eventually, the survivors were low on health, and decided to come out. We took advantage and ended up killing all four of them (we still lost on points). The chopper never came.