[At first he's just in disbelief that another Servant was taken down so readily, but the identifier 'a Jogomuro' would explain why it was so weak. Monsters make for poor Servants]

Then your Servant is...

[He lets it go, now knowing he's in a precarious situation. The fact he didn't sense another one meant either the man's Servant is capable of concealing his presence... or have the ability to attack remotely from quite some distance away - neither option is good.

Then the fire causes a commotion below them, people spilling out into the streets as smoke filtered inside, including his Master among the many]