Like we learn in "V", the human body can survive on 5 pints of blood, )Brit & Mallick(, so Dr. Gordon could possible have survived sawing his foot off. After all until we see his body we can't assume he's dead. I wanna bet JigSaw would've still needed a surgeon, e.g., to put the key behind Mike's eye in Saw II, I doubt he, Hoffman or Amanda could have done it themselves...
Yes, yes, both Brit & "Tweeker" Mallick are alive and well. .. They looked pretty f***ed-up at the end, when Erickson found their bodies, but ... Mark - no pun intended - my words ... BOTH BRIT and MALLICK WILL RETURN IN VI, and I'm *NOT* talking about flash-backs ...