But if the door gets opened that magnetic field will break which triggers another alarm.

一旦门被打开，这个磁场就会被打破，从而触发另一个警报。

They then taped those plates to the wall without ever breaking the field or setting off an alarm.

然后他们把这些板子贴在墙上，而没有破坏磁场，也未触发警报。

It sort of breaks up the visual field a little bit.

它有点破坏了视野。