She is being tutored how to debate outside under the trees by a creek at one of McCain's homes with two little lecterns.
Mostly she will throw some attack zingers at Biden to the point that Biden will look silly just ignoring them or refuting them. Believe it or not, this works for the person who virtually becomes a parody of themselves by relentlessly spewing outright lies and calls the other debater names. The defensive stance against this is percieved as a no win situation when ignored or refuted, at least to a shallow and ill informed audience

Sarah can deflect real questions well and give an unrelated stock asnwer in return.

Gwen Ivall is the moderator and has just suffered a [ainful broken ankle today.
If Gwen is medicated there will be some interesting moments for sure.
Gwen is understated, intelligent and demure most of the time so it is hard to imagine this moderator being insistent upon anything, which will give both people all the rope they need to Biden their time and dig a hole with a Palin shovel.

Hey I made a funny....