It's not like he had time to gather Sen-Chakra U_UPeople forgetting that Minato and naruto teleported an entire army, The army has no seals, but minato used the chakra cloaks as a medium for his teleportation. Now since sage allows you to become one with nature I don't see how its not possible for him.
But yeah His SM sucks hard time, he admitted it.
To initiate the transformation into Sage Mode, the user must remain perfectly still. And how much did he have ? Max. 10 seconds....