Heres what I would be thinking if I'
m him in this hand, lets get past the fact that he's in there with K7.....the 
flop comes down with the possible 
straight, 2 to the 
flush and me holding 2nd 
pair. The 
flop doesnt look like anything that would help a 5X preflop BB bet so when you bet out 1/3 of the pot i'
m thinking 1 of 2 things, you're holding something like AK AQ and missed the 
flop and are trying to 
take it down right there, or you're on a 
flush or 1 card 
straight draw. I dont think you've hit the 
straight because most people wont bet 1/3 pot if you flopped it especially with 2 to the 
flush it would either be a pot sized bet to 
take it down right there, or a 
check in hopes of the 
turn missing the 
flush and slowplaying your 
straight hoping to 
trap someone later. When the person in front of me calls your dollar that leaves what, 4 dollars in the pot and costs me 1 dollar to see the 
turn card. so for 1 dollar all i need to be sure of is that 25% of the time i've got you beat, if you'd make the same bet on a 
straight draw, a 
flush draw, or 2 overcards theres no way I cant 
call that bet and at least take a card off. 
The 
turn brings my 2nd 7, but also hits the 
flush, no help to the 
straight and no help to your overcards. You make another weak bet at the 
turn and I reraise you to see what exactly you  might have if you've hit the 
flush then i'
m expecting you to 
push right there and its easy to lay my hand down. You just 
call so the 
flush is no longer a threat to my hand and i'
m feeling pretty good that you've either got a 
straight draw or still clinging to your overcards, the 
top pair still isnt something i'
m considering, especially since i've got it 
dominated right now. The 
river brings the Ace and even though i'
m not liking seeing the 4th spade hit the board what i'
m really thinking about is the 
straight never came and if he's on overcards he just hit and i hope he bets into me. Since overcards were one of the hands I had you on and seeing the ace of spades hit i'
m more likely to think you were playing 
suited overcards as hard as you were. Even though you werent 
suited you had 
top pair with 
top kicker and that accounts for why you have stayed in so far, but i wouldnt have thought of that with the preflop and weak 
flop action. When you go all in with 4 spades on the board i'
m calling you but not feeling great about it but still pretty sure that i've got the hand won.