よっぽど悪いことさえしなきゃ...
Unless you do a really bad thing...
Is なきゃ a contraction of ないことには? I can find the latter in my text books but not the former.
Weblio suggests that it can mean both "Unless one ..." and "one must ...".
Would I be correct in thinking that the meaning is determined only by the position in the sentence. So, in my example sentence, if there were no following clause would it mean "You must only do bad things."
In summary I'm a bit confused about the usage in general. Any information (in English) would help. Thanks.