My first play through on Rimworld (permadeath), and I was doing "okay" until an unfortunate series of events doomed my colony of four:
Colonist #1 died when I decided to see what caravans were like. Sent him out, got ambushed and hurt pretty bad. Since he was not too far away, I had him head back. Died of infection on the way.
Colonist #2 died pretty suddenly of an illness.
Then the mad animal attack happened (Boomrat). I figured he would explode when shot, but unfortunately I could not get both my colonists inside. My colonist who was previously slowed by some malady or the other was attacked, and since she would clearly get killed by the rat without my intervention, I sent my other guy out with a rifle and tried to kill it before it killed her. He did, but it exploded, severely injuring Colonist #3 and setting my dog on fire. While I was rescuing Colonist #3 and putting her in a medical bed, my dog ran around burning until finally dying right up next to my base. Colonist #3 died of her injuries as the base burned around her, and Colonist #4 was severely burned fighting the fire. He did eventually put it out, but without the ability to self-medicate, he died soon after.