To be beaten very badly at something, especially in such a fashion that you were behind from the start and never had a chance. Comes from the Boat Race, an annual rowing competition between Oxford and Cambridge, in which the first side to get ahead can move to the middle of the river (where the current is fastest) and is almost never overtaken thereafter.
Ammo Racked is a term used among War Thunder players and World of Tanks players. This term refers to a catastrophic kill on a tank or turreted vehicle, which results in the Jack-in-the-box effect, which is when an ammo rack explosion launches the turret of the vehicle up into the air like the puppet in a Jack-in-the-box. However, the Jack-in-the-box effect only occurs on buttoned up vehicles.