I feel like he knows.
Generic alphas have super smell so i think he knows hes just asking cuz theres no pheromone release that drives alphas to rut whenever theyre near an omega.
yeah I think you are right. but seeing his expression was very ... um, how do I say that?
but the Omega is great at acting.(๑•ㅂ•)و✧
Hes revealed to be a cunning guy and he clearly has his goals set. I think he deliberately pretended to be nonchalant and went along with the omega's acting like hes playing with his prey. His thoughts prolly was like
"Hm, still not admitting the lie when you obviously arent in heat? Pfft-- Lets see how much further you can act huehuehue"
And poor little mc here taught hes beig a genius for deceiving his innocent coworker xDD
But does Alpa not know what else is in heat or not.
However i'm very curiousヾ(☆▽☆)