Each time Christy gets out of bed and escapes, the waveform displayed on her cardiac telemetry shows no sign of movement. Telemetry is very sensitive to movement, and even rolling over in bed produces a strong reading.
Christy has a telemetry unit next to her bed, which has a waveform on it, however Christy has no telemetry lead running from her arm to the unit. There are remote telemetry units which send a signal wirelessly, but even they require leads attached to the patient and a small transmitter somewhere on the patient's body.
Christy is working at the restaurant again, from which she was laid off in Cornflakes and the Hair of Three Men (2016), although it is never mentioned that she was rehired.