Delayed attack?

Background, Spinebreak him and rest a bit. Right before I trample him this happens. 1005/1039h(96%) 382/386m(98%) 785/785v 9 AM cave full 1911tnl> A duergar miner yells 'Kinrall! Now you die!' Autosaving. 1035/1039h(99%) 386/386m(100%) 785/785v 10 AM cave full 1911tnl> trample duer You mercilessly crush the resting form of a duergar miner underfoot! You feel a pair of heavy iron boots crush a duergar miner underfoot. Your trampling MANGLES a duergar miner! A duergar miner has some small but disgusting cuts. 1035/1039h(99%) 386/386m(100%) 785/785v 10 AM cave full 1911tnl> A duergar miner's pierce DISMEMBERS you! A duergar miner dodges your chop. A duergar miner parries your pierce. A duergar miner parries your chop. A duergar miner has some small but disgusting cuts.