Like other war doctors, Dunlop was faced with seemingly impossible tasks. After the Battle of Chippawa, Dunlop worked alone on 220 men from both armies because no other surgeons were available. The story continues that Dunlop worked alone for more than two full days, barely sitting down and stopping only to eat and change clothes. He played a more active role in the assault on Fort Erie on 15 August 1814, carrying about a dozen injured men out of the range of fire and providing survivors with basic necessities. He served with a road-cutting party near Penetanguishene in the spring of 1815.