Why do I get the values from "$n" and "$m" after deleting the respective symbol-table-entries?

#!/usr/bin/env perl
use warnings;
use 5.012;

package Foo;

our $n = 10;
our $m = 20;

delete $Foo::{'n'};
delete $Foo::{'m'};

say $n; # 10
say $m; # 20
perl symbol-table
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