Very scary!
I'm glad Piper is safe and sound.
Akitas tend to have a high prey drive. Plus, it's generally not a good idea when dogs meet to hold one while the other is 'loose.' I've read this relative to dog parks too. Ideally, a leashed dog should not meet an unleashed dog. in other words, they should meet on equal footing.
I understand feeling the pressure of allowing dogs to meet. Trust your instincts for sure.