I suspect devant is what is causing trouble. It doesn’t mean “in front of” here but is the present participle of the modal verb devoir.
Il devrait aller loin.
He shall go far. (It is anticipated that he will go far)
[…] comme devant un jour aller si loin.
kind of literally translate to:
[…] as “shalling” one day go so far.
Of course, there is no such thing like shalling but I guess you got the idea.