I said the same thing at first, but our 3b shove range is actually pretty wide. I'm curious how KQ does against a large portion of pairs + broadway hands + some suited ace blocker hands. KQ's ahead of all the broadways. i can't look these players up, but final table bubble a 21bb stack can certainly have a r/f range in the co, and moreso can have one in my head when he's flatted first. he may plan to call your shove but not once there's a flat. that range is a little snugger. 

All that said, I just looked up that player and while every post is blocked to me right now at work, it seems he's a high stakes reg. I don't know how I feel about it, but I'm going to run that when I get home.

Well why isn't your 3b shove range wider? 3b shoves are pretty much where your chips come from when youre at this stack size, and that's especially so when 5 handed. Youre too shallow to be 3betting when not all in. 

it's opened to 2x, called 2x, there's 1.5bb with antes and your bb and you have 18 behind.

There is 5.5bb in the middle and you have 18. This is an excellent 3b shove spot unless you know the flatter is trap-happy. When you shove, villain's get about 1.38 to 1, meaning they need to have 42% of your equity for neutral chipev. I don't know how much of an edge his hand needs over your range vs potodds to be correct given that it's a final table bubble, but it's 5 handed. co opens as a steal/wide some % of the time. you shove in easy spots (or not…youre shoving quite a bit tighter than i recommend) and he or the other opener should know this and would call wider. that said, you wouldn't want to shove too wide and too often, but this is definitely a spot for it.

if co opens 15%, he can't call all but like top 4-5% and that means he's raise/folding 66% of the time. flatter is probably 3betting some hands so you can take out some combos of like TT-QQ and AT/AJ. If you were to 3b ship a hand like A5s in this spot, the original raiser's raising and then call/fold ranges remain the same, but you've taken out a chunk of the ace combos. so while he still has 15% of hands and still calls 4-5% of them, he's less likely in this instance to have one of the hands that belong in the calling bucket. the same goes for the caller of the open. he's less likely to have AT-AK and AA because you have one of the cards. so that shifts his hands in this particular instant.

It's rather early in my day still, so forgive me in this math doesn't make sense or is off in anyway. I'm sure someone else can correct if you follow the route I've laid down.

Let's just highlight the 3b ship if the caller didn't call the open because I want to show you how you can exploit raise/fold ranges on the final table bubble especially. Villain opens 15%, calls 5%, folds 10%. These are arbitrary numbers that many players have approximately at this stack size. Many will call wider, many will call tighter because they're opening wider in the first place. honestly, it being 5 handed he's probably opening wider than 15% and calling wider than 5% but the ratio isn't going to get messed with too much. say open 20% call 7% for example.

anyway here's just against a single opponent. it's pretty close with 88 actually, which feels strange to me. i thought it would be more profitable. a hand like KTo does much better against a calling range than 88 does. it's only about 4% but that 4% works two directions to aid us in our ev calculation.

villain opens 15%, calls 99+ AQ+ that's 5%. folds 2/3 of the time, calls 2/3 of the time

2/3 (4x [his open+sb+your bb+ ante)) + 1/3 (.3 x 21 [+bb if you get called and win. 19×2+.5 ante + .5 sb])

– 1/3 (.7 x -18 [-bb when you get called and lose])

2.67bb+2.1bb- 4.2bb = +.5bb.

with KTo here in the same spot.

2/3 (4x [his open+sb+your bb+ ante)) + 1/3 (.34 x 21 [+bb if you get called and win. 19×2+.5 ante + .5 sb])

– 1/3 (.66 x -18 [-bb when you get called and lose])

2.67bb+2.38bb- 3.96bb = +1.09bb

after seeing this, I prefer flatting and deciding postflop with this hand because of the caller being a better player that should be snug to flat the open in the first place, and the same would go for other hands that flop well. you're getting 5.5:1 and only need 15% equity. you won't realize that equity vs two opponents without a hand that flops well because you won't see turn and river runouts (backdoor hands). after seeing i need 15% equity, i check that 1bb won't cause me to lose fold equity when 3b shipping or open shipping, and since we have 17bb when we whiff, we stlil do. foucalt pointed out that your stack change implications should be marginal decisions only though.