You tell me, man. One second he was fine, then out came the knife. I better get the guards.

我怎么知道？伙计！刚才还好好的呢，一会就拿上刀子了，我还是去找守卫吧。

youdao

For example, security guards should patrol on campus around teaching buildings and student dorms, and enforce strict entrance checks, barring entry to anyone carrying a gun or a knife.

例如，保安人员巡逻在教学楼和学生宿舍的校园，并执行严格的入口把关，禁止任何人进入拿枪或刀。

youdao