In last stands, such as the infamous 300, the ones mentioned in History of Rome podcast that Roman companies suffered in Spain and against Hannibal in Rome, all the way up to Custer's, what exactly happens with the last few people? I'm sure not all last stand's result in total massacres where everyone dies, but in the instances where that does happen, is there fighting until one side realizes there's no one left? Or did they just pelt them with missiles and arrows? My question more specifically goes toward larger battles involving thousands of people (so perhaps Custer's is a bad example in this context).
Custer's Last Stand took place on the first day of the Battle of the Little Bighorn.
Custer and his men were wiped out late in the afternoon of June 25, 1876, but he and his men comprised only five of the twelve companies of the 7th Cavalry that were present at the battle. About four miles away from what is today called Last Stand Hill the battle against those remaining units continued, on a segment of the same ridge line today called Reno Hill after Major Marcus Reno.
The entire battleground comprises over 11,000 acres, only a fraction of which is part of the Little Bighorn National Battlefield today.
Reno led the initial charge on the south end of the village with three companies and subsequently retreated to the ridge above the river's opposite bank, where he was joined later that afternoon by Captain Benteen's three companies and an additional company with the pack train carrying the 7th's supply of ammunition. These men were for a time under concentrated attack and then myteriously relatively abandoned by the natives--the time during which Custer and his men were meeting their demise on the ridge across the river from the northern end of the village. The Sioux and Cheyenne then returned in force to Reno Hill and kept up a withering attack for more than another day, until the village packed up and they made their escape into the Bighorn mountains. These remaining men of the 7th Cavalry were not out of danger until June 27th, when General Terry and the remainder of the cavalry still in the field for the campaign arrived at the battlefield after travelling south up the Bighorn River from the Yellowstone.