This plant is not a sequential bloomer. And if it was a sequential bloomer you would know if the was something to come since the next bud would have already formed before the bloom fell off.
It should be safe to cut the spike off since nothing more should develop, or just let it dry and snap it off.

The green part is meristematic tissue that could have made a second bloom. You would have known there was a second bud while the spike was developing though