Instead of cooling the core by air flow (like a/a FMIC or ST185 TMIC), W/A IC cools the charged air by passing the coolant around the IC core.
Think of an air-to-air intercooler core stuffed in an aluminum tank filled with coolant.
Then, you pump the coolant and let it flows through the system.
It carries the heat from the the core (which has charged air inside) and
releases it out at the heat exchanger mounted on the front of the car.
So, there are two separated systems (charged air and liquid)
The BOV vents pressure from the charged air system.
So, it has nothing to do with liquid system.