"Unlock the weapon safety, sergeant."
"Safety unlocked, captain!"
"Open the drone bay doors."
"Drone bay doors open, captain!"
"Couple the radar to the target computer, major."
"Radar coupled to target computer, captain!"
"Fire when in range, gunner."
"Range finder status light green, firing now captain!"
"Stand by for closing drone bay doors, sergeant."
"Doors closing, standing by captain!"
"Reload."
"Aye captain, ammo boys scurrying."
"Skipper, engage all engines full reverse."
"All engines full reverse, captain!"
"Captain, incoming cannon shot off the topside port bow!"
"Don't just stand there, power the shield booster matey! Take evasive action skipper! All hands to battle stations, go go go!"
"Captain, the drone is circling."
"Inform me when it fires, corporal."
"Drone firing captain, target hit."
"Will that drone be enough to take out that destroyer, sergeant?"
"Negative captain, we need a second drone."
"Just one more, corporal."
"Sir, yes sir, standing by for range, captain."
"All engines full ahead skipper."
"Aye captain!"
Okay, here's how you do it:
The drone is a homing missile that submunitions into itself. Its life outlasts its proxsafety, but it detonates and subs when it expires. The explosion looks like a random spray of blaze fire going outward, but is of course really just an explosion, with a blast radius large enough to damage anything that's in the range of the "blaze cannons".
Now you have something like every second or two a burst of lasers (with no smoke or anything, it just looks like bolts being fired) and the drone keeps going (it subs into itself with zero/small inaccuracy).
Minor detail is it fires every 2 seconds regardless of whether it's on top of an enemy. And if you want it to look like the drone isn't purposely shooting you when the ship you shot it at is right under you, make it so the drone's explosion won't hurt the firing ship.