So we have the following Graco Pack n Play (Broadstreet), which we love, as does our little 5 day old baby girl. I have a question though with the napper part. It has a vibrating unit that can be attached to it. Is it safe to have this run for multiple sets of time? It has a self timer that goes off after 25 mins, but we then kick it back on and have it run another 25. Is this safe for the baby. It vibrates the napper quite a bit even on low speed. Thanks! Well I guess I can't post a link since this is my first post.