111229 Running Intervals

Buy in:
10 Burpees x 2

RRPuP Step 12:
7-5-4-4-4

Metcon:
Run 10 min @ Z1 warm up run
+
Run 30 sec @ 90%
Run 30 sec @ 50% x 8
+
Run 60 sec @ 90%
Run 60 sec @ 50% x 4
+
Run 90 sec @ 90%
Run 90 sec @ 50% x 2
+
Run 10 min cool down run

Did this incorrectly. Did 1 sprint then 50% then walk recovery. Still got in some good work. Covered 5.5 mi in total.