What does Chillingworth mean when he says, “There was no one place…where thou couldst have escaped me—save on this very scaffold!” What is Chillingworth’s response to Dimmesdale’s confession?

In context, Chillingworth is telling Dimmesdale that he would have discovered his identity no matter what... that only death would have provided him (Dimmesdale) with escape.

Dimmesdale's response...

"Hadst thou sought the whole earth over," said he looking darkly at the clergyman, "there was no one place so secret—no high place nor lowly place, where thou couldst have escaped me—save on this very scaffold!"
"Thanks be to Him who hath led me hither!" answered the minister.