Fortunately the fix is simple and runs quickly enough: iterate the destruction.
thanks again for the info.

Testing: 131093
        Construct: 0.195811033248901     669487 Hz
        Walk:      0.0962779521942139   1361609 Hz
        Destroy:   0.0676219463348389   1938616 Hz
[download]

DESTROY
{
    my $head    = shift;

    $head   = delete $head->[0]
    while $head;
}
[download]