This is being brought to you straight from the strategy guide. While this works for any round that has buzzers it helps the most from round 82 to round 88 where you have 5 buzzers from each of the 5 spawns per round (except for the Jackbot / Gap-Shot round). If you run forward and stand in the doorway of the front spawn the Buzzers cannot hurt you. They will still try to instead of taking out turrets or you shields. Unfortunately, the only class that can shoot them from this position is the tank with his Jet Gun. The support can easily leash with the hurt gun by stepping forward a little and then back if he takes too many hits, but otherwise it is just used to to keep hardware and pro's from being taken out. There is another spot but that one is not mine to tell the world, sorry.
Because I stopped smoking crack this week, I thought that I would actually show people the position in the thread. Be aware, there are positions in the door that the buzzers can still hit you so you may need to adjust yourself a little to one side or the other to avoid all of the damage.