[Deadly, is this based on a previously created fiction, or are you making this up as you go?]
As Luke heard Deadly's howl, he had figured that the attacks were working, and continued his assult, but he was not expecting the sudden shrapnel blast, many of the needle like metal hairs piercing the ceramite and plasteel plates and some even breaking skin. Fortunitely, nothing important seem to be damaged, and the most major effect the spikes made was that it piss off Luke that he would be at the wrong end of such a cheap trick.
"You son of a bit..." but Luke did not have the time to finsh his insult before he threw his arms up to defend himself from another barrage of attacks. the arms took the blunt of the attack and was able to throw a counter punch here and there, but Deadly was quickly tearing the armor to shreds, and Luke could feel the claws digging into the soft flesh below. Luke would have to think fast, because blow for blow, luke would only win with a luck punch.
Ducking under a tail swipe, and Luke raised the power fist and slamed it onto the floor, causing it the crumble under the two combatents. Deadly had no doubt saw what was going on, and jumpped away. Luke, on the other hand, let himself crash through, and kept crashing through other floors, going past ground floor and into the underground levels below, until he finally stopped in a sort of tunnel, and a huge cloud of dust now floated upward through the holes Luke had made.
"Fuck that hurt. Let's never do that again" Thought Luke after his landing. He picked himself up, and pulled out some of the metal hairs that made him look like a blue pin cushion. One of the lesser known abilities of Space Marines is their advanced sense of smell, and by taking a wiff of the metal hairs, Luke would be able to track down Deadly. As the dust started to disperse, Luke quickly scaned the room he was in and found what he was hoping for. He picked it up and dashed into another room. How this battle will end depends on what Deadly will do next.