insert a primer into (a gun, mine, or charge) preparatory to detonation or firing
Another definition of the adjective "primed" is "on the point of or strongly disposed"--this could also fit the example sentence, but the chosen definition fits better, since the doctor is referring to two 18th century pistols that had to be primed with gunpowder in order for it be primed for safety.
I jumped out and came as near running as I durst, with a big silk handkerchief under my hat for coolness' sake and a brace of pistols ready primed for safety.
All round this they had cleared a wide space, and then the thing was completed by a paling six feet high, without door or opening, too strong to pull down without time and labour and too open to shelter the besiegers.
For though we had a good enough place of it in the cabin of the HISPANIOLA, with plenty of arms and ammunition, and things to eat, and excellent wines, there had been one thing overlooked—we had no water.
the act of tormenting by continued persistent attacks and criticism
I believe the readiness of our return volley had scattered the mutineers once more, for we were suffered without further molestation to get the poor old gamekeeper hoisted over the stockade and carried, groaning and bleeding, into the log-house.
The adjective "cavalier" describes Captain Smollett's attitude towards a man who had unsuccessfully tried to mutiny and who is now asking for a truce from outside a stockade. The noun "cavalier" can refer to an armed horseman or a supporter of a royal government. These definitions give more punch to Captain Smollett's later proposal to either bring the pirates back to England to be tried and hanged by the king or to shoot Silver in the back the next time he sees him.
We could see the man who carried the flag of truce attempting to hold Silver back. Nor was that wonderful, seeing how cavalier had been the captain's answer.
"Stove" is the past tense of "stave"--this shouldn't grammatically fit the example sentence, since Silver is threatening Captain Smollett with what he will do within the hour, but Silver is a cook and pirate who does not speak in Standard English.
Before an hour's out, I'll stove in your old block house like a rum puncheon.