Eb and flow of combat.
The movement of each team can be described as a fluid motion. Each enemy wave of attack being repelled by waves of your own.
You can use this thinking to describe an offensive push up the map. Attempting to push a fluid enemy whilst allowing as little to ‘spill’ through your drive. Any ‘spillage’ would result in the enemy leaking round the side or even straight through to your rear.
An enemy push can also be seen as a fluid wave that if you attempted to run from or into you would be swept away. If you hunker down you stand more chance of containing or diverting that wave.
This can be seen clearly in a map such as downpour, where the enemy push is usually up either side of the map. If they are allowed to spill through your defences then you have to deal with them sweeping round the rear of your position.
If however you can see the push coming you can either contain its flow with suppressive fire or alternatively you can divert it with accurate fire to force a different route to be used.