Is this a recent occurrence or has he always had trouble napping there?
(I think you answered that! sorry!)
Can you ask them to monitor it, and see what is happening at the 35 min, mark of his nap? Is there something environmental happening-- other babies going down at the same time.. or waking up etc.. sleeping noises etc.
Also, ask them how long the awake time is prior to going down.. it may need to me lengthened a bit.
Don't introduce the soother if he doesn't use one.
If it's recent, it may sort itself out. If it continues.. then some tweaking of his routine would be needed (ie. lengthening awake time) But really, he might be becoming more aware of his environment and the change of sleeping environments might be setting him off. Could they put him in a crib that's away from all the hustle bustle of the room (ie. in the corner of the room, furtherist (sorry, is that even a word??) from the door way, way in the back?
Hope this helps!