When a panel has determined that 28 U.S.C. 2253(c)(2) has been satisfied and an appeal and concordant stay are necessary, does an en banc court have authority to vacate these determinations and deny petitioner his right to appeal absent a finding that the panel has abused its discretion?

Could a jurist of reason find a state court decision concluding that the petitioner did not meet Panetti's required threshold showing of incompetence is contrary to or an unreasonable application of law or rests on an unreasonable determination of the facts when the petitioner presented evidence establishing that he lacks a rational understanding of the reason for his execution and the State has not presented any relevant evidence to the contrary?

Whether the state court's finding that the petitioner did not meet the Panetti threshold for incompetence to be executed was unreasonable under 28 U.S.C. § 2254(d)