Assuming it was possible for Pam, Lana and Cyril to make it to the ground alive after bailing out (see previous goof), none of them attempt to use their reserve parachutes to climb down from the trees they land in. This is standard (albeit anachronistic, for the time this season takes place) training for this type of parachute. Pam, being the most familiar with the parachutes, should be able to explain how to do this.
Pam, Lana, and Cyril bail out of Archer's plane wearing what appear to be static-line parachutes. At 1,000 feet, bailing out without an anchor cable in the aircraft to deploy the parachutes, there would be no way to open the parachutes before they all hit the ground. However, all of this is a dream sequence of comatose Archer, and dreams do not have to be factually accurate or make sense.
Cyril/Fuchs is attacked by a snake that coils around him. That means the snake is a constrictor. Yet, it has the long fangs of a poisonous viper. Constrictors have very small, albeit incredibly sharp, teeth to hold the victim in place, so they also bite before coiling. However, this is a dream sequence of comatose Archer, and dreams do not have to be factually accurate.
When Pam walks away from Archer at the end, the sound of heels clacking on the pavement is heard, but she is actually wearing boots or sturdy shoes. But in Archer's dream, he hears heels clacking on pavement.