Rats can be found in most indoor environments, including the Twin Houses. They are fast moving enemies that inflict little damage. However, they are almost always found in groups, which makes them a more significant threat.
Rats do not trigger a "chased" warning when they aggro on Daphne. They do trigger the "detected" warning. They generally have a small leash area, so except for tightly enclosed places, it is simple to move the opposite direction until they lose interest. However, they tend to be placed in or near areas that Daphne must reach. So, she must either kill them or simply tolerate their bites until she passes by them.