Live SNG-- push all in with 4 players left----was this the right play?

[mike1270]

this was the first time i played live. the SNG was down to 4 players and the blinds were 200-400 and going up in a few minutes to 300-600. i had 2400. SB has ~5000. BB has ~ 6000 and the BUT has ~12,000.
i was UTG w A7s feeling confident the SB and BB would fold but thinking that the BUT was 50/50 to call. was this the right move??