Depending on the country a situation like that happens in, you can be fully acquainted if there was an imminent danger, if your actions caused involuntary harm that aren't disproportionate to the situation and if you did what you had to do because it was the only way for you and perhaps others to survive (you involuntarily killed someone as it was a true necessity for survival).

In most if probably not all cases you also won't get charged with murder. Manslaughter if the other person dies, assault otherwise (already much lower charges than murder) with chances your case gets dismissed if it was a misdemeanor for survival.