The Legendary Pixel Crew

If they could somehow become cohorts of people involved in 20th level encounters and survive a single one... assuming 5 regular party members, they would level up at least once every encounter until they were level 11.
If you came from a very rich family, it might be something you'd gamble on. If you could afford 25k gold for true resurrection you only have to survive one encounter to go from 1 to just below level 3. If you survive that one, you're even more likely to survive the second encounter which would put your just below 6th level. The third encounter would put you at level 7.5.
How would you accomplish this?
First, have a high level family member with Leadership and Forcecage. It's not worth anything's time to try to kill you through forcecage, then they win the battle as normal. Easy powerleveling.
Does this make sense?
No.
Would any sane GM allow it?
No.
Is it technically rules legal?
Absolutely.

It should be noted this doesn't work unless the person with leadership is much higher level. At minimum level (7), a 1st level party member gets only 91 or 114 xp for a CR 7 encounter with 5 or 4 party members, which is about the same as doing a CR 1 encounter with a group of 4 (a normal sort of encounter). Experience nearly doubles with every 2 levels of the person with leadership. (going from 1/7 to 1/9 for double xp)
There wasn't really a point to this I just felt like mentioning how weird cohort rules can be.

For the record, this didn't work in 3.5 because XP was different. A first level cohort would have received a paltry 60 xp, similar to a normal encounter for them.

3.5 also didn't have the EXP table expand indefinitely. Even if you won a fight against a high-level opponent, if they were "too strong" the table didn't have any EXP award listed. So despite helping with winning, they'd still get nothing

Even winning solo you'd get nothing. Which sucks because our groups GMs LOVE throwing us up against things 12+Cr above our weight class.

If you could actually beat those enemies with them *really* trying to kill you, then you were either very powergamey (and possibly using different interpretations of the rules) and/or high level. At level 20, for example... a CR 32 isn't as unreasonable as fighting a CR 20 monster at level 8.
Anyway, if they actually expected you to fight those monsters, you should get xp. But definitely no more than the 10 CR higher monsters because the real challenge they posed couldn't have actually been higher than expected there.

In this case there were level 7+ people against CR 17, and they would have technically still received xp... but honestly those challenges shouldn't happen anyway.

Who's girl-Shen? I don't remember her off the top of my head.