I have to agree with Anastasiya on this one.
On the other hand, the FBI had just issued subpoenas in regards to Mike Flynn's Russia ties, a step up in the activity of the investigation, and it's not implausible that the firing of Comey really was a result of Jeff Sessions' recommendation to Trump. Recall that Sessions had to recuse himself from the investigation due to his own ties to Russia. Either way, Trump- or Sessions-instigated, this is not about Comey's troubling behavior regarding Hillary Clinton's emails, as the White House is pretending it to be. They've had four months to fire him for that.
...but hey, do what you want...you will anyway.