Currently the group were in the very early stages of the 5th floor and had a large amount of ground to cover before reaching the final boss. Although Sam and Lola were in a hurry there was still time for them to teach and explore the 5th and 6th floor as per normal. The time restraint took in their ability to find a suitable C-rank monster to hunt but now that they knew where one was, the issue was less time sensitive, Frost would be able to benefit from a full education. They also weren't worried about the ice revenant being killed before they got there given its power.
Within the [beginner's ice magic] monster lair Sam, Lola and Frost were likely the strongest group around and even with their abilities taking on an ice revenant was dangerous. The only reason they were was because of a dire need, therefore it was unlikely for anyone else to take it on or at least win.
