So how were the staff able to clean the room, and the police document all the suicides? Surely all that must take more than one hour.
Olin does explain that he strictly supervises the cleanings with the door open and makes sure that nobody's in there for too long. Presumably he followed a similar procedure for the police.
Perhaps the room is "intelligent" in a way, and only kills people who actually make reservations for the room with the intent of staying the night.
Mike hears that nobody has been able to remain in the room even an hour, with times to suicide ranging from a few seconds to a few minutes. However, after we learn how the room works, one realizes that those brief times were only in the beginning of the latest loop. We don't know how many loops they'd endured up till then.
With that in mind, now think about the "natural deaths" that also occurred in that room...
Given the room's evil and macabre sense of humor, how likely is it that the "express checkout" is Schmuck Bait, and suicide would lead to being trapped like the ghosts we see in the room?
What if the ending is simply Mike trapped in yet another loop?
The room blocked the cellphone, but didn't block the laptop. Why? Because there's been people in there to clean, and it's pretty likely that at least one of them has had a cellphone in their pocket. The room would figure out what those things are pretty fast - it's already figured out the phone lines, after all. However...it's never seen a laptop before. If the last paying visitor was in 1978, it's never even seen a computer before. So the laptop surprised it, which is why Mike got through on the wireless. It then broke it to stop him from doing that, and then once it had figured the computer out, decided to use it against him to get more victims. Because even evil hotel rooms need toys.