The Clan of the Poes (Page 157)

//Panel 5//
Clifford’s Narration:
NO PULSE…!!
Sheila:
Ah…ah…
//Panel 6//
Jane:
What a shame……
Your mother may have gotten drenched.

In a much earlier scene, Baron Portsnell had sharply reprimanded Edgar and reminded him of things he must never forget in order to pass himself off as human (reflecting in mirrors, making sure to fabricate a pulse when necessary, and so forth). So it seemed strange that a mature adult such as Sheila would forget such a basic thing. Perhaps being caught up unexpectedly with the doctor threw her off and she was careless. Or else she did not find it necessary in such a case, and her lack of pulse was only noticed by Clifford because he happened to be a doctor.