There's absolutely no reason to feed outside of their cage. If you're feeding outside of their cage because you have two bp's together, then you need to get them separate containers to solve that issue. People say to feed in a separate cage to avoid cage aggression, but that's just not true. Just about everyone here feeds in the snake's enclosure and there's no increase in cage aggression. Best case scenario, it does no harm or good to move the snake back and forth. Worst case you stress the snake out moving it and it refuses food (actual worst case would be regurgitation, but refusal is more common).
What eating habits are you checking out? What's this "just in case" that's causing you to feed live in another enclosure?