Whenever I spot a cockroach and get up to grab the insect spray, the little bastard runs like the hero in a movie when spotted by the bad guys. If I do the same thing with any other insect they just sit there until I return with their death sentence. Why?
IIRC cockaroaches run away from light so if you turned on a light to go after the bugger it is programmed to scoot.
In general insects are more a collection of in-built responses than thinking beings. Cockaroaches, given your experience, would seem to have innate in-built flight triggers that you set off by moving towards them. Some insects may have a different strategy such as holding perfectly still to avoid a predator. Which strategy is best depends on the situation and in your case the cockaroach has the better strategy.
Our concept of “smart” is not compatible with insects. They function on instinct and reflex. Cockroaches have the physical ability to run quickly and squeeze through tiny spaces, along with instincts and reflexes that are very successful in helping them avoid humans who wish to do them in. They aren’t smart so much as “skittish.”
The smartest are the ones you don’t see.
It may be worth mentioning that there is some talk of a “hive intelligence” (not sure what else to call it. The idea is that one bee (for example) is dumb as a brick but 10,000 bees gathered in a hive act in concert with each other that suggests the intelligence of the whole hive far surpasses its individual parts.
Not sure if there is anything to this (or just sci-fi nonsense) and I have to run so can’t Google on it now but something to think on for fun.