I was just starting out another colony. Things were doing good, and when the first raider appeared, I thought it would be very easy.
I had a guy with a rifle and a guy with a knife. The raider was some barbarian with a club. Surely I'd win.
The clubber attacked my knifesman first. They battled, but as it turned out that bastard had a level 8 melee skill. My knifesman, 4. He fell onto the sandbags.
My rifler continued to shoot at him, but the fire rate was too low. After knocking out one, the raider knocked out my rifler, picked him up, and started carrying him away.
I didn't know what to do, but my 3rd colonist, who couldn't fight whatsoever and was cooking meals, ran up to the raider and slapped him. He couldn't retaliate, and eventually he fell too.
Eventually, my colonists recuperated.