Both grandfathers were in WW2, one was a medic and captured in Crete, spent several years in a POW camp, the other in the Signals Division, first in North Africa then in Italy. Both were amazing men, but neither really talked much about the war. I only recently found out the story of when the one on Crete was captured [actually surrendered] recently.
After the main battle for Malame airfield (Germans invaded with paratroopers and took the airfield) there were a lot of guys hiding in the hills in caves with many wounded, some seriously. He was in a cave with a fairly big group of guys including several seriously wounded who didn't have much of a chance without proper medical attention, so they decided a group of them would surrender and carry the critically wounded down so they could get them to a hospital. And that is how he ended up being captured, basically giving up his own freedom to save the lives of his mates.
Then while in transit on the mainland of Greece, heading for Poland/Germany they were in a convoy of trucks with the wounded in the back, one German guard in the cab and a couple of them alternating the driving. The guard would regularly fall asleep during the night, and one particularly foggy night while they were at the back of the convoy they lost sight of the others at a T intersection. The guy driving decided they should make a break for it so they took off in the other direction away from the convoy. A few minutes up the road they stopped and check on the guys in the back and how bad they were. There were several in pretty bad shape who would have no hope of escaping and little hope of anything without the proper medical care they were receiving, so they turned around and rejoined the convoy, once again forsaking their own freedom to help others.
It kinda blew me away really, there must be thousands of other such stories of bravery and self sacrifice that have gone untold over the years because those involved would rather forget and try get on with normal life.