"There's something in his soul / . . . the hatch and the disclose / Will be some danger"
Is the answer
The tone( speakers attitude)can be frightened or grim and the mood (emotional affect the text gives the readers) can be worried or tense.
What I think he means is that the bystanders knew what was happening but didn't stand up for it. They didn't fight for the Jews rights. But in my opinion that statement is wrong since anyone who stood up or defended the Jews would be killed.