Let's make it a little less cryptic.

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper::Concise;

my $foo;
my $bar;

BEGIN { 
        $foo = '/foo'; 
        $bar = '/bar';
}

my(@dirs) = ($foo, $bar);
use lib @dirs;
push @INC, @dirs;
print Dumper(@dirs), "\n", join("", @INC), "\n";
no lib @dirs;
exit;
[download]

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper::Concise;

my $foo;
my $bar;

BEGIN { 
        $foo = '/foo'; 
        $bar = '/bar';
}

my @dirs = ($foo, $bar);
use lib::tiny @dirs;
push @INC, @dirs;
foreach my $dir(@dirs) {
    print Dumper(join("", @INC)), Dumper($dir), "\n";
}
no lib::tiny @dirs;
exit;
[download]