A) 50/50 with dead money in the pot is a great gamble.
B) "way behind" = ~34% equity against KK and ~12% against AA.
23% against { KK+ }
35% against { QQ+ }
38% against { QQ+,AKs }
40% against [ JJ+,AKs }
Add in fold equity. Add in the fact that everyone at the table saw you jam with AKs and when you do it with AA,KK, they're more likely to call with PP.