What Yeshua said here has nothing to do with fighting, or combat situations. He mentioned an instruction in the Torah where it says,"An eye for an eye and a tooth for a tooth." Let us go to a Torah instruction concerning this teaching:
Exodus 21:22-25,"When men strive together and hit a pregnant woman, so that her children come out, but there is no harm, the one who hit her shall surely be fined, as the woman's husband shall impose on him, and he shall pay as the judges determine. But if there is harm, then you shall pay life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burn for burn, wound for wound, stripe for stripe."
Let us highlight these:
1) surely be fined
2) he shall pay
3) then you shall pay life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burn for burn, wound for wound, stripe for stripe
Usually, eye for eye, tooth for tooth, deals with monetary issues. It would not make sense to knock someone's eye out, then gouge yours out and give it to the guy so that he can put your eye in his. Imagine the medical problems that would cause. Imagine the health problems!
So, when Yeshua said it, he did not leave the understanding of the Torah.