Kodiak Vent Steam while knocked down on your turn

Question to see just how great vent steam is. I've been playing 3 kodiaks with Harkevich for a while now. My first game into Bart was at the OTC that just ended. Can a Kodiak trample into Bart's feat, get knocked down after the movement is completed, and still vent steam? Since the knockdown happened after activation had already started, and vent steam is an anytime rule, I don't see why not? We called a judge and she ruled that I could.

But I thought that I'd post here to be sure and hopefully get some citations. 3 kodiaks trampling and venting into the front lines did a lot of work offensively and defensively.