Teammate

The people and zombies Clark first encountered frozen into popsicles had all met their demise at his hands.

"Arrogant, you think you can surely beat me?" Clark had initially intended to resist, but his body was significantly sluggish in such low temperatures. 

Even with acceleration, he could only recover to his usual state, whereas Eric, dressed in military green attire, was well-insulated against the cold. 

His specialized shoes rendered the frigid ground irrelevant to him.

"It's irrational to fight him alone!" Clark made a beeline for the small door.

Though he didn't know who was behind the door, it was apparent they weren't allied with Eric, which could greatly assist Clark.

So, Clark decided to assess the situation inside first. Even if the person inside didn't help, delaying Eric for a while would be beneficial.