Oh, the list of things that garlic can do to people who<em>aren't</em>immune to its toxins is quite startling - and could certainly help to explain its use as a way to find the rare lurkers among the general population who just aren't quite the same as everyone else.  The 'hidden' perils of what we eat (and what people's bodies can, generally, effortlessly cope with) can be quite amazing.  ;)<br/><br/>But yes: Petra could confidently expect to survive breathing Venus's atmosphere.  The odds are that anything Sybil is willing to cook with ingredients she has aboard the Odyssey, Petra'll be willing to try!