As a followup on this answer from another question, the Gemara on Pesachim 8a seems to say that a shaliach mitzvah, someone who is doing a mitzvah or on the way to do one or even on the way back is protected from (seemingly all) harm/damage/loss/danger (provided it is not especially dangerous). However in real life this doesn't seem to be the case. I personally have two examples of this off the top of my head:
- My grandmother, while walking home from Shul in a relatively safe area, was mugged. She only lost property.
- A couple years ago I was biking on campus, trying to rush to meet someone after class so we could go to Mincha on time and so he wouldn't have to wait. Normally a young guy like me biking on campus, even if hurrying, isn't considered something particularly dangerous. But when crossing grass, some other biker came up on the path ahead perpendicular, I tried to stop quickly to avoid hitting them, but I braked and I lost traction and fractured my hip. I was in plenty of pain, had setbacks in school, there were of course monetary costs involved, and while mostly healed I still am not completely back to normal.
So why do events such as these happen if the Gemara seems to promise protection? Are they not "covered"? Does the protection not apply?