I am going to answer this without ICMizer, just to show how I might play this life with no tools. I think it is either a shove or a fold. Calling the cutoff for a third of your stack and then folding to a big blind jam seems like it would be a disaster and pretty exploitable. Again, I need to know how the big blind has been playing. Is he just punishing the table with any two cards, or has he picked his spots well and perhaps gotten a big stack with a monster against second best?

If you were in the big blind and were last to act I think A2s would be a profitable call on the CO shove. But with big blind and his monster stack still to act, A2s does not seem like it would play well three way if you jam and get called by big blind and his monster stack (or if you call cutoff, BB jams and you call that jam).

Even if BB jams light you are either behind or not that far ahead of most anything he could have. Let’s say BB is a complete maniac and he shoves with 3d, 8h. You are still only a 63-37% favorite, and let’s be honest he isn’t jamming with 3d, 8h. So let’s put the big blind on something more reasonable like Kd, Jh. You are a 60-40% favorite. If big blind has 10Js, you are a 53.54-45.95% favorite. But do you really want to play for your stack with these scenarios making you a mild favorite with you having 17BBs? Maybe, maybe not. But these are the absolute best case scenarios. Not let’s put the big blind on something else reasonable like Ad, 9h. Now you win 28.39% of the time, lose 56.52% of the time and chop 15.09% of the time. Let’s say big blind has 5d, 5h. You only win 33.36% of the time.

I don’t love it. I think my gut would be to pick a better spot. I don’t know if that is GTO, but that’s my honest assessment of what I would do in real time without using ICMizer.

Again, it would be helpful to know what style big blind has been employing to better analyze this hand.