You can run pudb inside Zope but because of Zope being multi-threaded you need to patch urwid.raw_display.py to not send signals. Simply replace code in def signal_init(self) and def signal_restore (self) by a simple pass or create a monkey patch for it (Simon Pamies).
Sometimes it seems that pudb is not returning control back to zope because it stays on top (no screen redraw) but hit some key and if the keycode appears in the upper left corner you're out of pudb.
Todo: When quitting pudb redraw screen (problem in zope perhaps due to no SIGWINCH sent) - could be fixed by explicitly resetting screen upon exit