Here’s the eyewitness report, courtesy of The Dark Knight Rises Community on Facebook:
“Eyewitnesses and crew members told us of a particular scene being filmed,” the site reports, “where a bald-headed child wearing ragged clothes emerges from the well and pulls his hood over his head. From the conversations, we reckon this is a young Bane, emerging from a vat of Venom, trained by Pence’s Ra’s al Ghul. The years of addiction to Venom builds him to be a massive monster with amped up senses, intelligence and physical prowess.”
Granted, the “report” is entirely hearsay but it would offer a compelling explanation for Nolan’s inclusion of the Lazarus Pits as well as how Bane will fit into the real-world setting – not to mention the reason for the Ra’s al Ghul flashbacks (as portrayed by Josh Pence). That said, there’s no actual evidence that points to the assertion that the pool is actually a Venom vat – so it’s fair to say that the eyewitnesses here are making a lot of assumptions. So take this particular set of details with a grain of salt.