[In his haste answering messages from House and Sherlock and trying to get out of the morgue he was in, it's a little while before Mycroft sees this. He's mad at House--again--for inspiring Kid--Mycroft is cold-hearted, yes, but he's not a monster and this is absolutely appalling.
Audio, Day 259
He immediately tries to call Kid back,]
Hello? Are you there? Have you revived yet?
@Kid, audio, evening 259
Don't be so dramatic. You and Dr. House are both being ridiculous.
[Translation: yes. He has revived.]
Perma-audio
Why on earth did you do this experiment? Where are you?