Take the following measures immediately to minimise the damage after the MacBook gets wet:

1. Turn off the MacBook immediately: If your MacBook gets wet, please turn it off immediately to prevent further damage. You can press and hold the power button until the MacBook shuts down. This is because almost all circuits on the logic board are powered when the MacBook is powered on, and liquid containing impurities flowing through powered metal can cause corrosion and short circuits due to electrolysis.

2. Disconnect all external devices: Disconnect all external devices, such as chargers, USB devices, Thunderbolt devices, etc., from the MacBook.

3. Dry any liquid on the surface of the MacBook: Use a dry, absorbent cloth to wipe up any liquid on the outside of the MacBook. Avoid pressing the keys, as this may cause the MacBook to turn on and increase the damage.

4. Wait for the MacBook to dry: Let the MacBook sit and wait for it to dry. Avoid using a hairdryer or other heat source to speed up the drying process, as this may cause additional damage to your MacBook.

Due to certain circuits on the logic board of MacBook, such as PP3V8_AON and PP3V42_G3H, remaining powered even when the device is turned off to supply power to certain chips and wait for startup commands, it is important to seek professional repair services as soon as possible after the MacBook gets wet to assess any damage and perform necessary repairs, in order to avoid further corrosion and damage to MacBook parts.