Obviously Weiss's extremely powerful perception was not going to miss this kind of things. But she was not sure about what was the exact reason behind this sudden intense hostility.
The feeling that Weiss got from the men keeping an eye on them was not just that of simple caution. Instead what she felt was intense hostility.
There was not that much killing intent mixed with the hostility. Instead, there was a lot of lust. From this combination of emotions, Weiss gusessed that these men wanted to capture them alive for neferious reasons instead of killing them outright.
Peria's perception was not strong enough to sense these looks and hostility but Elise was able to somewhat sense them. Evem though she was not specialised in perception, because of her realm of a high level knight, her perception was already stronger than normal.
