Esc is always available while you're typing (and usually available when you're not). Holding Fn is for getting at the F-keys, not for getting at Esc (though it

Esc is always available while you're typing (and usually available when you're not). Holding Fn is for getting at the F-keys, not for getting at Esc (though it can be used for getting at Esc too if you're in a context that normally hides that key).