go under
US /ɡoʊ ˈʌndər/
UK /ɡoʊ ˈʌndər/

1.
2.
意識を失う, 眠りにつく
to become unconscious or fall asleep, especially due to an anesthetic or exhaustion
:
•
The patient began to go under as the anesthesia took effect.
麻酔が効き始めると、患者は意識を失い始めた。
•
After a long day, he just wanted to go under and sleep.
長い一日の後、彼はただ眠りにつきたかった。