it can't go off

go off
离开
I'd better have waited till the rain went off.
我当时要是等雨停再走就好了。
私奔
She went off with the gardener's son.
她跟园艺工人的儿子私奔了。
睡着
He has gone off by the fire.
他靠着火炉睡着了。
消失
The headache went off quite suddenly.
头疼突然消失了。
开始变坏, 变质
Fish soon goes off in this hot weather.
在这么热的天气里鱼很快会变质。
变差
The lecturer used to do well, but he seems to have gone off now.
这个演讲者以前讲得很好, 但如今似乎变差了。

离开,但是没有上下文,没法理解

它不可能凭空消失。
这里的go off 是消失不见的意思。

二楼正解！

如果是枪的话，go off 的意思是放火