Active player gets priority
Active player maxbands Geiger
Geiger maxband begins resolving
Active player chooses to trash and return to play Unit X
Unit X is trashed and returned to play all as one 'continuous action'
Game checks ongoing effects at end of first line of text being executed (in this case, we have just one line of text as part of the overall ability, but mentioned here for completeness)
Game looks for things to add to the stack.
It finds a leaves ability that triggered
It finds an arrives ability that triggered
It asks active player to order them
Game checks to see if anything is in the process of being resolved
It sees that Geiger maxband has completed
It proceeded to execute the next thing in the que
This should hold true for all non-que-buster effects