Austin was at the top of one of the buildings in the middle-town—keeping an eye on the house where the medic lives.
His plan was to take advantage of his regular visit to the palace and replace him as the medic by using the mask of disguise.
Once he was inside the palace, he could meet the former king in person and help him with his illness. And in exchange, he would ask for peace between Eryndor and Drenovar.
The reason they targeted Eryndor in the first place was because of their ancestors being killed during their visit to Eryndor.
And if they could become angered at the death of their deceased relatives, they surely would get appeased if Austin saved one of their living relatives.
Or so he hopes. However, if it doesn't happen and Austin finds himself being cornered then he has two routes in mind to escape. One of the two might put Valerie in danger that's why he was thinking of using the second method.