How about something along the lines of i.e. untested :-), the following...

use warnings;
use strict;
use autodie qw/open/;

open FILE, "<file1";
my %results = map { chomp; ($_ => []) } <FILE>;
close FILE;

open FILE, "<file2";
while (<FILE>) {
    next unless /^(Event|Code) -(\d+)-/;
    my $code = $2, next if $1 eq 'Code';
    push @{ $results{$code} }, $2;
}
close FILE;
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Obviously, you'd need to put filters in place to handle whitespace e.g. blank lines in file1...