| During the game when he flipped over 79o I was saying to myself, "WTF?!" but afterwards the pot odds made some sense.
Still I think it is interesting because his stack was around 40-45k, maybe a bit more. He was shortstacked earlier and had doubled up a couple of times recently. So preflop his M was about 4.5 with an adjusted M of 2.7. This is preflop before he posted the BB. By calling the bet he does get great odds but that does leave his stack down to 37k.
Before the hand he was probably 3rd out of six. One big stack in SB, another stack a little bit bigger behind him and then one other stack a little bit less. If he loses to me then I willl have 48k in chips and jump in front of him. He would slip to 4th out of 5 at the table.
If the 1st raiser wins out then the BB would get back about 12k assuming that he wins the sidepot with me.
So this is what the BB should see preflop:
An all-in push from a shortstack. Could be playing any two cards. Against 79 probably at least 1 overcard, possibly 2.
That all-in is immediately called and raised by another small stack. For another short stack to go all-in must have a decent hand. Most likely 2 overcards maybe even a pair. He had seen me bluff all-in earlier at the other table when I was short stacked and I lucked out on the river. This time though I'm calling a bet and not doing the 1st in vig.
So in all he is probably playing against 2 to 3 overcards, maybe 4 total. There might be an overlap if both shortstacks are playing Ax, Kx, etc. Some of his cards may be counterfeited as well if someone is playig A9, A7, K9, K7, etc. So what would be his overall win % against most hands?  | 
