I thought the chances of winning if you call and win are outweighed by the hugely increased chance of busting in 4th if you call and lose (which you will 35%-40% of the time, even against random hands). This might be a difference between the lower and the upper buyins. In lower buyins, the two medium/shortstacks are folding way too much and pushing way too infrequently. Thus, you can continue robbing their blinds as well as occasionally stealing from the other big stack. This situation is made even more fun if one of the medium stacks gets really short. If everyone was playing perfect or near-perfect bubble here, I guess your call makes more sense. Interesting post.