I agree he could have been in survival mode. He may have just wanted to have as much time as possible to figure out what on earth to do. I would bet that he considered a lot of different things -- trying to hide the body in a different place within the building, trying to move her out of the building in some sort of container, who knows what else. He could have known that she would be found, but hoped that either she wouldn't, or that at least the defense wounds would be healed by then and he might have a ghost of a chance of getting away with it.
Maybe he thought there was a shade of a chance that the smell of the lab would cover the smell of her body and that people would believe that she had left the building during the alarm. He could have hoped that people would conclude that something horrible happened to her after she left (Amistad really is in a lousy neighborhood) or that she had been somehow carried out of the building in a suitcase or garbage can.
He may have figured he didn't have anything to lose by trying his level best to get away with it, and everything to gain.
We don't know how normal his behavior was in the days following the murder. We know that some who've seen the video footage outside the building thought he looked agitated. We know he missed two baseball games (the day of the murder and Thursday). We don't know if anyone very close to him knew anything was "off" (but not why). The only thing we know is that from a distance he seemed normal the day he was arrested, and that people on his baseball team, who didn't know him particularly well, didn't notice anything.
