Thane was hidden well. He could see Kasumi cloaked in the far edge of his vision. (having had his vision altered on Kahje allowed him to see ultraviolet light, which Kasumi’s cloaking device didn’t hide.) As he watched the purple tinted thief, he noted that she did indeed have Joker’s hat. Unfortunately, there was also no point in her searching where Thane was guaranteed to acquire it. So he let her wander in search of him.
Next, Kasumi left the Cargo bay area altogether. Apparently to find him elsewhere. This was where Thane spring into action, keeping himself as quiet as a shadow. Shortly after he started moving to follow Kasumi, his omnitool caught his attention with a message from Kasumi. It said that she was feeling something off, and the two of them would have to finish this some other time.
Though Thane would have preferred to continue the battle of sneaking and wits, he respected that Kasumi may be unwilling to partake in the fun and games whilst under so much stress. Thane sent her a short message saying that he understood, and that next time, the prize would still be the hat.
At that point, Thane decided to go and preoccupy himself in his room, likely with meditation, and perhaps a message to his son. However, as he was in the elevator, he received a message from Legion on his omnitool, offering another battle of honing skills. This time with regards to sniping.
Thane re-read the message. Zaeed and Garrus were also invited. Of the three, Legion presented the biggest challenge, with his mechanical precision, speed and greater lack for potential error versus himself and the other two who, while good, were not machines.
Thane was looking forward to some sort of honing of his skills, and this seemed as good a chance as any. He sent Legion a message saying that he would be waiting in the cargo hold for them, and proceeded there himself.
Once he had retrieved his sniper gun, his specialized HMWSR that had an interesting story as to how he had acquired it. When he got back to the cargo hold, Thane sat in a corner, and waited for the others to arrive.