I have only ever seen one person in my fire team get 2 blue engrams. The other 2 members either get one blue engram and one rare item or 2 rare items. To use septic as an example. I race to get to the first part where the entrance is blocked. I kill everything else after that point. I am only a lvl 28. It takes me by myself very little time to kill the low level guys if I choose. So either way I am not too far behind players who rush anyways. 9 times out of 10 I find myself getting there just in time to revive them because they rushed and the other members did not. Play how you want it doesn't matter to me. Sometimes I rush. Sometimes I don't.