Borderlands 2- ARID NEXUS BONEYARD - Complete All Area Challenges and Find All Vault Symbols

Challenges this level (Timestamps below): Cult of the Vault (2 symbols) Dead Air (switch off Hunter Helquist&radio before killing him) Under Pressure (Summon a wave of droids and kill them all) 0:09 First vault symbol is on the side of the turret tower at the edge of the area near the fast travel station. 0:51 Second Vault Symbol is found near the pump station, it&up on top of the eridium pipe. Use the nearby ramp. 1:15 Under Pressure Challenge. The button to summon the droids is on the north side of the map by the catch a ride station. All you have to do is kill all the droids, you can do it even if you get killed. Just come back and keep fighting til they are all toast. 4:41 Dead Air Challenge. Hunter Helquist (a sort of Alex Jones/Rush Limbaugh figure) is on the top floor of a little building north of the fast travel station. The building&elevator doesn&start working until after you turn in the last story mission and accept the "This Just In" mission from Mordecai though, so you can&do this one when you initially come through this area. It&said that you can sneak up on Helquist (you just press the y button when you are close enough to him to turn off his radio before killing him to get the challenge) but I really don&think it can be done, tried more than once in the past. Just bum rush him and be ready to spam Y, you&be close enough before you know it. I screwed up and ended up dying and falling off the roof because I got a phone call in the middle of...