Actually, in Season 2, Episode 3, 'The New Pup,' they've already had an episode where a snowstorm hits and Everest has to perform a rescue. But I guess they could always do a follow-up. They'd have to be careful not to rehash old plots though.

For 'Pups Save Marshall', maybe Marshall could get stuck while responding to an emergency, and the other pups have to work together to rescue him. It'd show the importance of team work and also focus on Marshall overcoming his usual clumsyness!