Imgor had problems to worry about, as he stood right behind the beast, and had probably aggreviated it too much. He had to get away from it, quickly.
Without time to think, his familiar reacted, and the ground directly below Imgor collapsed, causing him to fall into his mole's tunnel. The soil surrounding the hole wasn't too stable, and the hole quickly closed, leaving only a cone in the ground.

The collapse of the hole had also buried Imgor, but that is what usually what happens when you enter a tunnel by collapse, so his familiar was quick to dig him out without breaching the surface. If only he had his switch-weapon, this fight would be easy. The chitin plating of beats of this size usually doesn't stand a proper pickaxe swing, provided it hits. His bow was useless against the chitin, and the knife would only work against the joints between the plates, so he was left with 3 options:
[list]
[*]staying underground and wait the fight out
[*]attempting to stab the beast from below the ground
[*]leaving the tunnels in a proper distance form the fight and then return[/list]
He attempted the 2nd option, and thus used the tunnels to get below the beast, and thrust the knife upwards through the soil. He constantly knew the beast's location using his tracking spell.

When breaching the surface with his knife-hand, Imgor felt something; foilage, mostly dry, lying on the ground. It sparked an idea: If he was to ignite the foilage on the ground, would the beast survive?
He couldn't tell if he had stabbed the beast, or failed at the attempt, or if the beast had even noticed it, however, Imgor retracted his hand until the fingers were barely touching the foilage. After telling his familiar to get out of the area and leave an escape route behind for him, he cast 'Minimal Sparks' to attempt to ignite a fire. He hadn't witnessed Arnold arriving, so when he checked if Alex was still nearby, which he wasn't, he completely missed the passed out hunter. If the fire did ignite, it would most likely spread uncontrollably within the near vacinity.

Imgor ended up casting the spell 3 times, before it got too hot for him to keep his hand up there. As he got away, he crawled through the tunnels as fast as he could, and as his arm wasn't in the tunnel's roof anymore, the ground below the beast, if it hadn't moved already, would likely collapse soon.