Found the following hamletworks.org entries referring to line 506

View Commentary Note for 506
506 Be wary then, best safety lies in feare,1.3.43

View Immaterial Textual Note for 506
506 Be wary then, best safety lies in feare,1.3.43

View Material Textual Note for 506
506 Be wary then, best safety lies in feare,1.3.43