影视英语口语:低调行事

“低调行事”在英语口语里能怎么说？

蹩脚口语：keep quiet
地道口语：under the radar

影视来源：《识骨寻踪》

剧情引导：
Hodgins发现身亡的CIA职工身上居然有一个窃听器，Booth和Brennan调查到这个窃听器注在他同事Mindy名下。Mindy只好承认自己与之恋爱的事实……

Brennan: Rutledge said the bug was checked out in your name.
Mindy: I got the bug because I was afraid Greg was cheating on me.
Booth: So why didn't you mention this before?
Mindy: We weren't supposed to date. I guess it's not like the FBI. We're not allowed to sleep with someone we're working with.
Brennan: Wha-- is she talking about us?
Booth: We're not.
Brennan: No.
Mindy: Oh, it okay, I'm CIA. My lips are sealed. Greg and I were under the radar, but a week before he went missing, Greg broke up with me. I guess I got little too jealous.