The Beastmaster's retort is simple: another shot from their explosive rifle thunders around the expanse of the cavern, the detonation's force pushing Dust narrowly past a patch of oozng lava. Theres a very faint whine from the servos of the strider's frame as the reds and oranges of lava and explosion are cut through with a thin blue from the frame's inbuilt brachial jets as it speeds away, the grace of the escape only slightly offset from a retort by Thanatos. As they decelerate to standing, the blunt end of the explosive rifle becomes capped with a the heavy, cylindrical end of a siege mortar. Aimed high for a parabola-shot, a gauntlet locks down over the Beastmaster's free hand-styled like a pair of jaws over the wrist- and wreathes it in a sphere of energy as the frame extrudes a rapidly solidifying cube of 3D print material. The cover raised by this device is utterly negated by Biff's downward cleave on Dust's targeting solution, a blow that cuts deep into the strider at the shoulder of the arm used to raise up it cover.

Near deep enough to part the the limb from the frame.

The enemy scout moves to engage, the spindly legs underneath it lending the frame a suprising amount of speed. It unholsters a small, box like configuration of a gun that begins to spool up with the same sort of quiet whine as the strider's jets. Crude lights emanate and fan out from the box before coalescing at Dust and onto points that highlight the damage already done by the Beastmaster. The light stays where it is as the Scout turns off the marker rifle. The Scout continues its as it engages its own limb structures. The reactor adds to the sounds with a curt scream and the much louder sound of accumulating heat as the Scout backpeddles, a curious charging sound adding to all the noise, a tone that builds to some sort of phantom pinnacle.

And then the Scout and Strider become awash in reflections and refractions, all blended together and jumbled with the jagged angles of rock and the light of the lava. The stealth drive installed into the Scout's frame winds down in time with the cacophony of all the conflict at play.
Spoiler: OOC: Strider Turn 2 & Scout Turn 1
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After Dust's turn but before Biff's, the Beastmaster took their second turn of the round as per the elite template.

The beastmaster moved 4 spaces then they
Shot at dust with its explosive rifle for 6 damage and knocked them back three (through a lava patch-we can discount it if its not visible to people but they should be now)
They then boosted 4 squares into the center of the zone and switched to their Siege Kit, which lets them deploy a size 1 piece of hardcover (the cube in front of them) and lets them scatter a size 1 AOE of difficult terrain that persists for the rest of the combat (bright red square within the smoke-to differentiate from the Hives AOEs which will be dark red/burgundy on r20).
While moving they were overwatched for 3 damage by Thanato's Shotgun.

Biff then took their turn. Following this, the Scout took their turn

NPC Turn 3
Scout Moved 6 Spaces.
Boosted 3, hit Dust with its marker rifle. Dust is locked on and shredded while they have this lock on
The Scout then completed its boost and boosted back 3 spaces to where its first move had left it.
It then overcharged per its limitless trait to pop its cloaking field- gaining 4 heat and the following effect: NPCs within three of the scout are invisible (50/50 chance to hit-roll a d6, evens hit, odds miss). This effect lasts until the end of the scouts turn and the scout is immobilized while its active.