I do not know the solution to your problem, but I added a print to your death sub:

print "removed=$removed, ", scalar @chroma, "\n";
splice (@chroma, $removed, 1);
[download]

This gives you more info about why you get the splice warnings. You can also add use diagnostics; which explains your splice warning in more detail:

splice() offset past end of array at foo.pl line 154 (#1)
    (W misc) You attempted to specify an offset that was past the end 
+of
    the array passed to splice(). Splicing will instead commence at th
+e end
    of the array, rather than past it. If this isn't what you want, tr
+y
    explicitly pre-extending the array by assigning $#array = $offset.
+ See
    perlfunc/splice.
[download]

Hope this helps.