Sentence:  They promised faithfully to bear their confinement with patience, and were very thankful that they had such good usage as to have provisions and light left them; for Friday gave them candles (such as we made ourselves) for their comfort; and they did not know but that he stood <WSD>sentinel</WSD> over them at the entrance. 
Meaning of the word marked with <WSD> tags:  A sentry or guard.