Your right, Ca channel blockers are a big no-no, but why not LR? I guess the K? It didn't think it had enough to make a huge difference but NS would probably be best and safest.
Watching the CO2, as one person suggested, is the earliest sign but if they transferred them to the floor then they were not watching CO2. This whole situation sounds somewhat strange to me. Did they not find out about the MH until after the case was done? Was it a direct relative or was it the 2nd cousin once removed? If they knew there was a chance before hand then they should have prepared the room without triggers (new or thoroughly flushed machine and no succ's within a mile of the room). If there was a real threat then they should never have left PACU.
Also, if you would have caught the MH by his temp then it was probably too late. Temp is the latest sign, as someone said, and the whole process has been going on way too long if you caught it that way.
If there was a real concern about MH then whoever sent them to the floor was negligent.