Let me try to explain how I see both cases:
52o in the BB:
First, let's suppose UTG bet more than you had because he's not folding to your push so, if I haven't miscalculated anything, you need to put in 197,693 in chips to call and there's 461,693 in the pot so you're getting around 2.3-to-1 odds. That justifies a call against two overcards, but you're doomed against a PP. How often will you be against overcards or PP? Difficult to know, anyway, I'd fold.
83o UTG:
Even though the table's been quite loose I think you got some FE here, so you can just push and take down a 184,000 pot.
If you push and you do get called by someone other than the blinds you're risking 285,693 to win a 469,693 pot, that gives you 1.6-to-1, screwed against a PP, breaking even against high cards, and that's certainly not better than the odds you get by calling the 52o but you do get some FE by pushing first-in UTG that you don't get by calling in the BB.
And if I'm gonna play a crappy hand like 83o or 52o I'd like to have some chance of taking the pot down without anyone contesting it.
But your FE is not that great either because the BB would be getting nice odds to call given your short stack.
Anyway, both cases are marginal, my opinion is that hero just waited too long to make a move and his stack just got too small, so I'd rather move first-in UTG before the blinds reach me and leave me really crippled. But since he waited for the blinds to get to him I'd rather fold the 52o and push first-in if with any hand in the next orbit or pray to the poker gods that I get dealt something decent. ♦
But what do I know? I finished in 3719th place when my TT didn't hold against the other guy's AK. 
EDIT: Oh, and since I'm reading Harrington right now I'm gonna take this moment to say that after the blinds go through, hero will be, as defined by Harrington, a pokerwraith.