Continuing from the post below

Notice, as bad choice as that would also be, this is not like the guy suddenly found the house on fire and he did not check on the other person before trying to deal with that fire. There checking on the other person is part of the solution while here it is also part of seeing the problem itself. That is because only if the noise came from someone else it would have been a problem.

The status of continued confidence or lack of suspicion in that his girlfriend did not leave the bed conflicts with the status of being surprised by the sound. As much as that alleged hearing of a sound was surprising as much as there was more reason to establish or eliminate the other person being its source by checking his existence in his place. The defendant's alleged behaviour seems far from being natural especially if turning the head toward the person would have sufficiently check the existence of that other person, let alone when one also walks all that distance near the bed from the balcony according to the defendant's allegation. And what called for such level of confidence that his girlfriend was still in the bed? It seems that there are reasons for her to be awakened starting from his move from the bed beside her then going to the balcony and doing all what he alleged doing. I don't think that I also need to point out how very often people go to the bathroom when their sleep gets interrupted.