The sedative poison of the wasp being injected, the area of the sting begins feeling dull, and expands. Seeing as the rune was useless even with a wasp being in direct contact with him, who crouched in the center of the rune, he decides to run for his life, before the sedative slowly paralyzes him temporarily. In his haste, he forgets to 'defuse' the rune by covering up essential parts.
Using his spell he locates Alexander, Joshua and Nickolaus, and runs towards the closest one, Nickolaus.
The wasps obviously chase their prey, and have no trouble doing so, due to their ability to fly.