The vassal looks at the nearby spider and begins silently cursing in all the languages it knows. It can't get away from the oversized vermin! It can just barely stay ahead of it.
Desperate, the vassal flies straight up to 115N85E50H.
(Round+1) Confident it's out of range of the vermin, the vassal then stows its flail and moves to 115N25E50H.
(R+2) Able to take a breather and think, the vassal moves to 65N25E20H, drawing it's javelin. If the spider is within a 15' radius of 65N25E (i.e. within 30'), the vassal throws it's javelin at the beast.
(R+3) In what might be final stages of the battle, the vassal dives at the spider, readying it's flail during the dive, and attempts to smash the spider into chitinous bits.
(R+4) If that doesn't kill the spider, the vassal smashes the spider with its javelin, and tries to sting the spider.
==
That takes us to the draw point if everyone misses.