Had people under buildings...there heads sticking out of the cement floor...shooting me...watch the floors in buildings! This is gonna get to be a problem I can tell.
Being able to get under the map in the beta was caused by bugs in the NET code, which can be fixed quite easy by updating the servers without a patch, It will most like stop once EA get the servers sorted. Log-in to Battlelog and leave a message on the bugs/feedback
forums of which map or maps you have seen it happen, this is the best way to let DICE know directly about bugs players encounter.