ya novel (?) girl with purple eyes important to some facility, trying to break out with a boy named james who can teleport

[erinnicole]

i’m trying to find this book i read forever ago, and this is literally all i can seem to remember. at the end of the third book they were falling into a huge pit that might have been the grand canyon ?

 

[Ursa major]

Could it be The Universe Between by Alan E. Nourse?

This novel, which is a fix-up of two shorter stories (High Threshold and The Universe Between), came up in two other searches: one in started in 2007 and one started in 2010.

If you follow the links, some of what appears in the books is described (as various people, including me, try to work out the name of the book).


Note that there's no mention of a third book, but there is mention of the novel having three parts (possibly the two novelettes already mentioned plus some extra material (new or from something else by Nourse). (Wikipedia has a list of works by Nourse here.)