The expert modes are completely the same as the "normal" modes except for other scaling of the stats.
I ran this floor 30 times now and didn't have any problem. I suggest to check your computer system because your "loading too long" can happen due to a weak internet connection or bad synchronization with your party members (because their internet has hiccups or their system is too slow).
Also I never had a monster stuck anywhere in my 30 runs. And I am connecting from Germany which means that this is not a latency problem.
I suggest to check if your or your party member's internet connection is weak, the wifi signal is weak, checking the anti-virus solution if it is constantly working on your HD slowing down loading processes and checking your firewall solution if it might wrongly identify Dragon Saga network packages as hostile and blocks them.
Also I would recommend to check if you or your party members have other applications (like games, downloads, streams) running in the background which are slowing down the PC and/or internet connection.