From all accounts this morning, the White House 1) didn't think there would be an uproar about firing Comey and 2) his staff was caught completely flat-footed. You can see by watching Sara Huckabee-Sanders with Tucker Carlson that they don't really have a rationale.
Fortunately, she learned how to lie and obfuscate at the feet of a master.
The Washington Post this morning:
After Spicer spent several minutes hidden in the bushes behind these sets, Janet Montesi, an executive assistant in the press office, emerged and told reporters that Spicer would answer some questions, as long as he was not filmed doing so. Spicer then emerged.
“Just turn the lights off. Turn the lights off,” he ordered. “We'll take care of this. ... Can you just turn that light off?”
[...] Spicer repeatedly batted down bipartisan calls that an independent prosecutor be assigned to handle the investigation into ties between Trump's campaign and Russian officials, saying that the current system is working just fine. CNN's Sara Murray noted that Trump has now fired Comey, who is leading the investigation, and Sessions has had to recuse himself.
“Right now, on multiple occasions, they said that the president wasn't under investigation. What are we investigating?” Spicer said. "...What are you investigating?”
Hear no evil, see no evil...