Agent Aaryan cleverly surmised that perhaps thermodynamics was the key to, well, the key. So he summoned up the maximum amount of water he could with his will to speed up the ice melting.
A new agent, Binary, was originally confused about the strength of his own will, and attempted to create an 'agent multiplicator', which, since summoning intelligent creatures was against the Green Gate's rules, did not work as he had planned, but instead, only served to agitate the water, which in turn, sped up the convective heat transfer process.
The key was now free. Now they just had to get to the top. Agent Aaryan had already considered a way to do this, but he would need some help. There were other ways as well, and the agents pondered which path to take.