Just watched it! Here's my question...

It was a fun action flick, but how come the bad guys were so heavily-armed in the first 20 minutes, when they were machine-gunning the SWAT team, but then later, when the main good guy (whose name escapes me) was going from floor to floor fighting for his life, everyone he encountered was armed only with knives and machetes.

Was this inconsistency ever explained in the movie?