I would feed my tropical scorpions (Pandinus and Hets) meal worms and super worms.
A) hold it by the head with 12" tweezers (so that it would twirl around) and then hold it in front of the hide to entice them and they would pull a snatch and run maneuver.
B) just drop them into the hide and most of the times they would get them, if not... in a few weeks I would just remove the wondering darkling.
C) or section it up into 1/4s, mostly I would do it that way when I was feeding the babies. (that would take along time though)
a buddy of mine fed a mouse to his p. imperator the other day and it was the saddest thing i think i've ever seen. before he threw it in there i was all for it but after about forty five minutes of the mouse continuously getting away from the scorp i just felt so bad. if the mouse wasn't in such terribly unhealable shape at that point i would of kept it. shortly there after the mouse was too tired to try and get away and it met it's demise.
I feed mine lobster roaches. I pick a suitable size and crush their head so they die right away and then i drop it in front of their hide. They almost always find it. It's typically gone by the morning.
I found unless u want to see the kill (which lets be honest must of us do like seeing from time to time) worms are the worst, they just burrow, the scorp gets um in the end but changes are u wont see it!! something more active that doesn't burrow!