I think he thought Kvothe would kick their asses. I thought it was supposed to be part of Bast's goal of making Kvothe remember who he is and that Bast doesn't want to accept that Kvothe is really off his game. The Kvothe we've been hearing about could have taken those two guys easily, so I don't see anything malicious in what he did. I could be wrong, but I see Bast as trying all kinds of ways to reawaken the badass Kvothe. I have to assume he has already tried all the gentle ways he can think of and now he is getting desperate. He must think Kvothe can have a hand in stopping the war.