To say Perseus was currently not in the best of moods would be an understatement.
He was cranky, angry, and frustrated, all of which was of course due to a storm of reasons that hit one after another consecutively.
One was that he had been on the march throughout the night, meaning he was sleepless, tired, and hungry.
He was meant to get some food after taking the manor, but that never happened due to the second reason, i.e.- 'his house' being set on fire by some scoundrels.
And tying to that same reason was how he had to now face the bitter pill of disappointment at having accomplished his goal of taking the manor but still not having achieved the desired result- i.e.- the capture of the city.
As for why, well came nicely to the third reason- Cambyses's escape and the fierce counterattack under her order, one which had them pinned to the hill and was slowly whittling down.