Assange also claimed he had a "poison pill" file he'd release if he were arrested.
No he didn't. I challenge you to find a single quote from him saying anything even remotely like that. All the "poison pill" stuff has been speculation by commentators and pundits regarding the insurance.aes256 file - but Assange hasn't said one word about what that file is or what anyone might do with it.
Direct quote from Assange himself:
The Cable Gate archive has been spread, along with significant material from the US and other countries to over 100,000 people in encrypted form. If something happens to us, the key parts will be released automatically.
Source: http://www.guardian.co.uk/world/blog/2010/dec/03/julian-assange-wikileaks (last answer)
Granted, he didn't mention insurance.aes256 directly, but I'm not aware of any other encrypted archives being distributed on such a large scale, so I can't imagine what else he could be referring to. Also note that he said "if something happens to us," not "if something happens to me."