You could try something using the:
$` ($PREMATCH) and $´ ($POSTMATCH)
operators.

So he should slurp in the whole file all at once into a string and apply a match to it. Then seems like you're suggesting he will have to

open my $postmatch, '<', \$' or die $!;
[download]

and search while(<$postmatch>) (or to use some trick along these lines). Very, very smart indeed...