Stupid but lucky

Idk how this guy plays, or why he made this play...he has not seemed too bad besides this play...anyways here how it went down.

first to act (i'll call him #1) raises 3 times the big blind (up to 480), next guy thinks a couple seconds and moves all-in (700) (#2) folds to big blind (in for 160) thinks for awhile and then makes the call (#3)...flop 53A, #1 check, #3 check...turn 10, #1 check, #3 bets 320, #1 calls, river J, #1 checks, #3 raises pot (somewhere around 2,100 chips) and #1 with KK folds... #3 shows 42o

Now how in the world can you see a 3 times BB raise, followed by an all-in, and then make the call with 42o? i wasnt involved with the hand haha but i was just so confused how n e 1 can make such a crazy call...would you have made that call?

more like how can the guy with pocket kings now re raise all in pre flo

that would make a lot of sense to to push hard, my guess was he was trying to slow play it, and he said the ace scared me off the action (his reason for not betting, just calling after the flop and folding to the big riase)