one shouldn't bury one's head in the sand while leaving one's bottom exposed

secret camera; hidden camera

(weaponry) hidden/concealed weapons

conceal, cover up

(colloquial) current boyfriend

everything

(slang) Alternative form of 彼氏 (kareshi, “boyfriend”)

everyone, one and all

気を付ける: to be careful, to watch out; to take care

to light a fire / to set on fire; to ignite; to set fire to / (figuratively) to spark; to ignite (excitement, debate, controversy, etc.)