в течение 15 минут он писал в тишин

в течение 15 минут он писал в тишине не отрывая глаз от того что он писал

Results (English) 1:

within 15 minutes he wrote in silence without taking your eyes off of what he wrote

Results (English) 2:

within 15 minutes, he wrote in silence staring at the fact that he wrote

Results (English) 3:

In 15 minutes he wrote in a quiet do not lift your eyes from the fact that he wrote