Yep, I'm sure there's a way to take all cameras out within 10 seconds, shouldn't be too hard with 4 players and all on skype (sorry I'm playing on PC, plus accuracy )
I'm gonna work out where they all are, draw a map, and split it into 4 zones so that I can give each player an area to take them out... should be pretty fast. Bugger the guards, the cameras go first above all else.