Step 5 iterated holder.items live while handlers move and destroy pieces: normal 博士投影 splices itself out (the next item on that holder was skipped) and 突变细胞 transforms its holder (the next item ran with a holder that was gone). It now walks a copy and runs an item only while it is still equipped on its still-owned holder; the rule is in the header and META.md. Tests use a synthetic spy handler after the 突变细胞 and after 博士投影.