Im not sure how you can ONLY put the SB on middle pairs.. why wouldnt he shove with higher pairs? What about AK?
I dont feel its a coin flip for you.. its more like 60:40 against.
Def more info needed on blinds and chip stacks of other players.
IMO you dont want to be calling a shove with 2 high cards.. you want to be the one shoving so that you can gain fold
equity.
Everytime you shove, people reduce your shoving requirements so if you shove 3 times with near garbage and dont get called AND then get AA preflop, people are more likely to call it with nothing and you get your double up.
Its all about luck but fold equity isa powerfull tool.
Usually when I get Short stacked in a SNG and the blinds are large, I can get it all back in around 3 shoves, before people have realised what I'm doing (I play fairly tight most of the time).