A player who plays a medic in the Battlefield series who instantly revives his teammates at inappropriate times (e.g. when there are still enemies near them), causing them to most probably die again very soon afterwards, which will have a negative impact on the revived soldier's KDR (for as far as they care about that).
A medic typically performs Rambo revives when he is a n00b just to get lots of points or does it for the lulz when he is a troll who likes to fck his teammates.
The "Rambo" part comes from the typical Rambo-style dash into groups of enemies just to get points for reviving teammates lying there. However, unlike Rambo, it is very that they both die in a matter of seconds.
Soldier: *dies while fighting enemies close-by*
Medic: *revives soldier* I got ya all fixed up!
Soldier: *dies again by same enemies*
Soldier: You just pulled another Rambo revive on me, FFS STOP REVIVING ME F*CKING MORON, MY KDR IS DROPPING BELOW 1 THIS WAY!!ONE!