In *Return of the Jedi*, Luke takes a blaster (using the force) before falling into the Rancor pit.  When he is next shown - now in the the Rancor pit - he no longer has the blaster.  However, it doesn't appear that he drops it on the way down in the previous shot.  So, what happened to the blaster?  Is this a mistake that was made in production?

(The part that I am talking about is from around 24:46 to around 25:00 in the 2011 release of the special edition.)