ok, ill start.....
tis my opinion and not based on actual facts, i'm too lazy to look stuff up tonight.
ITS A TV SHOW, NOT REAL LIFE- ITS RIGGED
now i dont mean rigged in that the pirate has been stacked to win, but they are looking at the effectiveness of weapons-not reaction of man. If we want to look at that, one could argue that the knight would have been worn out just getting to the beach, running after the pirate, hefting all that armor around and therefor would have lost by default. So with that in mind, i would rule out any time line constraints.
To light a grenadoe, slow match could have been used in this scenario. Other than the legend of Black Beard, i have not heard of anyone else carrying it under their hat. Carried in a can designed to contain lit slowmatch, its a matter of transferring the "cherry" of one match to the next, igniting the grenadoe. It happens all the time on a cannon line. PSSST- hey mate, me linstock is out can i have yer cherry? Sure, here ya go. Voila- second linstock is lit. Timely? No, but imagine a dozen of these things being flung at you from a group over the course of fifteen or thirty seconds. I'm sure the slow match can has a name, but i have no idea.
The firelock on the beach firing? Maybe. Its a 1/3% crap shoot to start with.
End result, its a show.