1.5 miles in 11mins 55 is 7.5mph average. To do it in 10mins you need to average 9.0mph.
To do this, you need to break down the 1.5miles into a set of shorter repeats where you cover the whole distance at the required pace, but with rests. I'd do the following:
9.5mph (overspeed!) for 2 mins, 1min30sec rest, repeat 5 times, so 10mins at 9.5mph total.
Next day, recovery run 30-45mins maybe 6.5-7.5mph.
next interval day, bring down the recovery time by 5 secs. Keep repeating this pattern putting in appropriate rest days and MEGA STRETCHING after the intervals especially the hamstrings/quads. Bring the rest period down to around 15-30 secs. Once you are at this point, you should be able to drop the speed by 0.5mph to 9.0mph and cover the distance if you really nail it.
Remember warmups, and stretching. The harder the session planned the more careful the warmup should be.
If you can't do 5x2min 90sec rest, the try 120sec rest. If you need more than 3min rest, bring the speed down - you are a long way off 10min 1.5miles.
