score:1
Thinking about what you could have done and should have not done is part of NΔ«varaαΉa more particularly Uddhacca,kukkucca. Since you cannot turn back time or remedy the situation it is best you do not worry about this. Worrying will aggravate the situation.
If you knew the sparrow was in danger but chose it to ignore it this is negligence. This does not amount to killing but this may have karmic consequences.
If you did not occur that the sparrow was in danger and if hit the fan and died there is no karmic consequences.
Upvote:0
"What is the purpose of skillful virtues? What is their reward?"
"Skillful virtues have freedom from remorse as their purpose, Ananda, and freedom from remorse as their reward."
https://www.accesstoinsight.org/tipitaka/an/an11/an11.001.than.html