live tourney, 60 runners, 30 left, 9 paid, average stack 6000.
blinds 100/200 15 minute clock, you have 4600 and are in the SB, table has been pretty tight since the start.
EP limps, passed to button who raises to 600. you call with

, BB passes, limper calls.
2000 in pot
flop

check, check. button pushes allin for 3100.
you know the button usually plays aggressively but has been unusually quiet in this tourney
limper to act behind you has approx 10k behind.
do you call for 3/4 of your stack?
please, no opinions on the play of the hand up to here as I'm the button in this hand, interested in the decision my opponent in SB had