I know mobs aren't beholden to the normal rules of lag that PC's have, but is casting and zapping within the same round as expected?

A mage merchant utters the words, 'wunsohar yarh'.
A stabbing headache rips through your skull, disorienting you!
A mage merchant's mental jolt STAGGERS you!
That really did HURT!
A mage merchant's punch misses you.
A mage merchant zaps you with a shaft of fiery yellow citrine.
A mage merchant's hellfire maims you!
That really did HURT!
Your pound grazes a mage merchant.
A mage merchant has some small but disgusting cuts.

I was only fighting one mage merchant, so not a question of multiple same-named mobs.

Mobs are not beholden to the normal rules of lag, and they can have multiple sources of commands that allow them to do neat stuff like that.

That really did HURT!