I always find it best to try and change as few parameters as possible in a cue. In Q146 you change both the mode and the speed. A few possible solutions:

1. Try setting the mode to "Play Once Forward" in Q142. This should be fine because pause should hold it. If pause is stopping it from presetting to frame 150, you could try playing at full speed and just bracketing frame 150 with in and out. So now it's basically just playing frame 150 over and over again until you change your outframe in Q146. <Edit: in order for this bracketing to work, you may have to set mode to "Play Loop Forward">

2. Rather than changing play mode in Q142, try changing play speed to "full speed" in Q142. Now the only thing you are changing in Q146 is play mode, and also possibly the inframe from 150 to 151.

I think option 2 here is going to be the cleanest solution.