Will an average citizen kill one person to save five?
Probably.
Will they sacrifice themselves to save 2 others?
Depends on the person and obviously the situation, but probably.
If they had to kill one of two people, and one is begging to be killed to save the other, which will they kill?
The person begging to be killed, because they are requesting it.
If an endangered animal was about to kill a citizen, would they kill the animal?
Depends on the animal, but probably.
- if yes, what if the animal was an endling?
Endling? Well, if it was truly the last of its kind, and the individual in question was conscious of that fact, they would likely try to find another way to separate the two rather than kill. If it truly is impossible... they would likely kill the endangered animal.
If a person who saved 2 lives before was trying to kill someone, would they allow it?
This is so abstract that answering it is pointless. Who and why did they save the other two people? What is the motive for killing the person they're about to? All of this would factor into a decision.
- If no, how many people would they have to save beforehand to get allowance?