I like that as well. A couple concerns I have, though:

First, even though "key-pair away" is colored, which would normally catch the eye more, it has less contrast than "is only a," which will tend to reverse the emphasis.

I think keeping both lines in the solid purple keeps the main focus on "FREEDOM" and secondary focus on "key-pair away." If I really want to ensure that is the case, I can make "is only a" a bit smaller, or less bold, but still in the same font family.

Second, this is going to be printed on a shirt, and gradients don't always print well. I know solid colors will print cleanly, so I will probably stay with that on the keys and the accents to the side of the middle line.