Just my speculation- It's very possible he or they thought they planned a perfect crime.
And if it didn't unfold according to what they expected, they may have been shook up.
That's when errors are often made.
I’d agree that the attacker then had his hands full anyway you look at it.
And he sure didn’t want to be caught with that gear so throwing it out randomly might have seemed to him his best bet for disposal under the circumstances.
imo