It's the first time we have such an accident. Our son used to have small scratches and minor bruises but this... 

Pre-story
DS (2 y.o.) has an excellent habit of transferring part of his toys into our bedroom. Each day - different toys. We are putting them back every day telling him "let's bring the train (blocks, cars) back in its place (home) " etc.
This morning he was especially enthusiastic and brought lots of mega-blocks into our bed. DH was cleaning and has put all the toys into a mesh (we have for some toys), to put it back into DS's room later on, and moved it aside.
Story
DH was playing with DS on our bed, usual things, hugs, pretending plane... Then, son noticed his mega-blocks in the bag near the bed.
Everything happened so fast, he leaned off the bed, tried to reach them, but fell off the bed and landed on this fucking bag with his face.
He cut the skin under his eye and scratched the eyebrow. Guess it was the opposite side of one of the blocks.
He cried for several minutes in my lap, then went back to jumping and playing with some cars, smiling the rest of evening.
We cleaned the wound and put some healing gel. He did not tolerate the cold compress though.
DH went to work feeling incredibly guilty (I understand him) and I can't look at my son's eye without tears.
I was in the room; everything just happened so fast, DH had no chance of catching him. Still so so so upset. Guess we are quite lucky it's not the eye itself.
Do these things happen or are we just the clumsiest people ever?