[Low] AKs in bb 5 from money with 18bb facing RFI. Call or jam?

Sub 20bb in these positions very easy jam.
Iff we are talking life changing money like it was the WSOP main or EPT main and you qualified in you could probably flat and play it very cautiously.

18BB is an easy rejam size, yes.

5 away isn't as close as it seems when that's still 25% of the remaining field.

Usually not a good idea. If hero misses - and they will do that about 7 times out of 10 - they're now out of position and in a difficult spot unless they hit a strong draw.

Playing cautiously because even a min cash would mean a substantial contribution to your poker bankroll makes sense if it really is a cautious play. But thing is that given the circumstances it's not, as Nath already commented on. In this spot Hero probably won't be able to fold into the money. And on average they won't be dealt a better hand than AKs before they start to get dangerously short. Even if they do wait and do get a good hand later on their stack have dwindled and they will have less fold equity. So now definately is the right time, even when playing with scared money.

Of course a cautious play would be more warranted if there instead were 200 ITM places, 205 players left and Hero was say somewhere around 180th place. That's not only because they should secure the mincash. Doubling up in such a spot doesn't increase your chance of going really deep in the tournament as much as it would if you double up with 25 players left. Hence the gain is sometimes not big enough, compared to the risk of bust when you get called. In bigger online MTT:s this is a reality, and when short stacked you should learn to estimate under what circumstances you can fold into the money and play accordingly.

The somewhat contraintuitive conclusion that follows from this is that you are sometimes more incentivized to risk your whole tournament life when you have a bigger stack and are higher up the ladder in the tournament. If you are say around the 80th position instead with 205 players left a double up would mean you're probably will be top 30-40 and have a real healthy stack, that also can start to abuse the bubble. Plus you have more fold equity, even against players that cover you.

I'm jamming here.

There have been times where I get knocked out. At Foxwoods in a $230 (probably) the CL raised late position I was in a blind and I jammed with AKo and he called with Jx (I think it was J7o). Its one of those things that happens. But like 5 to 7 out of 10 times I will double up when called and winning 5 blinds when I am not called is a good thing too.

Typically I will flat AKs in the BB when there are multiple players in the pot or HU where in both cases there are very big stacks and I have a lot of chips too and don't want to play OOP in a big pot. It also means that my hand will be hard to know what it is.

Here because CO will likely open wide, there is a good chance to take it down preflop with a jam.

Thanks all. Didn't realise 18bb shallower than I thought and 5 places away from ITM is further than I thought.

Good point on min cashing 200th place vs 20th place, never thought of it like that.

Yes agree too this is a common spot to get knocked out. V actually called with KJo, which surprised me and I lost.