Well, tripping hazard in a padded room? Not really a problem, your will always fall adequate padded But I planned to have padding above the grate. Center position is easier on the slightly slope one needs to have the water running to the drain and not forming puddles. Have it in a corner would be dificult for the existing construction.
And for the bed, it would offer to much attacking surface if it was like a shelf, and a hiding place that can make an extraction quit difficult and hazardous for the staff. Of course it doesn't look so nicely, but in this case, functionality comes before aesthetics.