Economics? They could have rendered him harmless with less but who knows exactly how much that would have required? It’s not worth the chance.
How much is a pound of C4 compared to the hospital bill if they didn’t make sure it would kill?
I always say if you’re gonna blow something up, “blow it the hell up!” He killed 5-cops for nothing.
Sounds like a standard M112 military charge. Not too expensive and the bang isn’t as big as one might guess. About right for blowing off a car door or a heavy entrance door. The robot survived.