Heat.

The carriage carrying the Terrans moved through a secured pathway, from the spaceport to the palace directly. Shi Lang was busy with his exchange with Captain Ameris, while the others were talking with each other using morse code. The content of their conversation was the surrounding elements. 

The pathway was guarded by armored guards carrying slender weapons. Rosa asked, "Pardon me but Captain Ameris, may I ask you something?" 

Ameris replied without turning back, "Please do." 

Rosa asked, "The weapons carried by the guards seem like melee weapons, but given your technological advancement, should they not use phasor weapons?" 

Shi Lang was sitting across from her and his expression turned cold. Rosa realized her mistake looking at him. She asked about weapons and what does a civilian has to do with weapons? 

Aremis caught on to it and asked, "I did not expect you to be a weapon expert, Miss..." 

"Rosa Blues." replied the lady calmly.