It was NOT his private room, it was a room he shared with Ravi, he had no expectation of privacy. On the first encounter he misled Ravi regarding the duration of the encounter, and on the second there does not appear to be any indication that Ravi agreed to give him privacy.
According to the timeline in that article, he asked Ravi for private time, but when Ravi returned at 9PM he found out that "private time" was for the entire night. Ravi was expected to find somewhere else to sleep, not his own bedroom. It is not surprising for him to have been pretty POed at that point. Wouldn't you be?
Then, two days later he does the same thing, but only AFTER he has been posting online about it and requesting a room change. There is no way he would not have been aware that Ravi was very annoyed by the previous days events, so it was a provocative act. Clementi knew what Ravi's reaction was going to be, but went ahead and did it anyway. The only reasonable reason would be to elicit the obvious response he knew he was going to get. It is pretty clear that he was looking for drama/fight and was prepared, setting up a paper trail. If he was not being provocative the logical thing would have been to request a room change and not entertain guests until he moved, to maintain the peace. He didn't do that.
And then the next day he jumps off the bridge, even as Ravi is texting him to defuse the situation.
It is quite clear IMO that he was unstable, and there are probably other things going on in his life to precipitate this.