By coincidence [Eldrazi Monument] was actually in my hand when I made the fatal mistake of
not noticing Felidar last week

My next turn was to play the monument and use Charge Across the Araba for
about 200 damage in total, then if that wasn't enough there was this
combination:

1) Sacrifice token creature to monument, which puts counter on twilight
drover
2) Pay 3 mana to put two tokens into play from the new counter on twilight
drover

So not only is the monument paid for, I get a new token creatures as well
:-)

I had Swords to Plowshares in my deck to deal with the Platinum Angel. That
would have worked because if it was bounced while you were on negative life
I think you would have immediately lost as soon as it left the table.