Curiously enough, the McCanns are doctors and Kate describes that she monitored the twins.
Panicked as she was (about Madeleine) she checked the twin's clinical readings and saw nothing to her undue concern (about them).
Then (much later) they (the McCanns) were accused, via a misconstrued comment of the twin's granndfather, of drugging the twins and all 3 of the children and (naturally) wanted to set the record straight.
What is 'clinical' about putting your hand on a child to see if it's still breathing?
No, and that was the other thing, she kept going into the twins, she kept putting her hands on the twins to check they were breathing, she was very much concerned in checking that they were okay. But they were okay, I mean, they were fine, they didn't, they were asleep, but at the time it did seem weird, I remember thinking, you know, when the Police came they turned the lights on, there was loads of noise, obviously from the moment Kate discovered that Madeleine was gone, the screaming and the shouting and there was a lot of noise and they, they didn't, you know, so much as blink'.
http://www.mccannpjfiles.co.uk/PJ/FIONA-PAYNE-ROGATORY.htm